Differential impact of test performance characteristics on burden-to-benefit tradeoffs for blood-based colorectal cancer screening: A microsimulation analysis

OBJECTIVES

To inform the development and evaluation of new blood-based colorectal cancer (CRC) screening tests satisfying minimum United States (US) coverage criteria, we estimated the impact of the different test performance characteristics on long-term testing benefits and burdens.

METHODS

A novel CRC-Microsimulation of Adenoma Progression and Screening (CRC-MAPS) model was developed, validated, then used to assess different screening tests for CRC. We compared multiple, hypothetical blood-based CRC screening tests satisfying minimum coverage criteria of 74% CRC sensitivity and 90% specificity, to measure how changes in a test's CRC sensitivity, specificity, and adenoma sensitivity (sizes 1-5 mm, 6-9 mm, ≥10 mm) affect total number of colonoscopies (COL), CRC incidence reduction (IR), CRC mortality reduction (MR), and burden-to-benefit ratios (incremental COLs per percentage-point increase in IR or MR).

RESULTS

A blood test meeting minimum US coverage criteria for performance characteristics resulted in 1576 lifetime COLs per 1000 individuals, 46.7% IR and 59.2% MR compared to no screening. Tests with increased CRC sensitivity of 99% ( + 25%) vs. increased ≥10 mm adenoma sensitivity of 13.6% ( + 3.6%) both yielded the same MR, 62.7%. Test benefits improved the most with increases in all-size adenoma sensitivity, then size-specific adenoma sensitivities, then specificity and CRC sensitivity, while increases in specificity or ≥10 mm adenoma sensitivity resulted in the most favorable burden-to-benefit tradeoffs (ratios <11.5).

CONCLUSIONS

Burden-to-benefit ratios for blood-based CRC screening tests differ by performance characteristic, with the most favorable tradeoffs resulting from improvements in specificity and ≥10 mm adenoma sensitivity.

Detecting salivary host and microbiome RNA signature for aiding diagnosis of oral and throat cancer

OBJECTIVE

Oral squamous cell carcinoma (OSCC) and oropharyngeal squamous cell carcinoma (OPSCC) can go undetected resulting in late detection and poor outcomes. We describe the development and validation of CancerDetect for Oral & Throat cancer™ (CDOT), to detect markers of OSCC and/or OPSCC within a high-risk population.

MATERIAL AND METHODS

We collected saliva samples from 1,175 individuals who were 50 years or older, or adults with a tobacco use history. 945 of those were used to train a classifier using machine learning methods, resulting in a salivary microbial and human metatranscriptomic signature. The classifier was then independently validated on the 230 remaining samples prospectively collected and unseen by the classifier, consisting of 20 OSCC (all stages), 76 OPSCC (all stages), and 134 negatives (including 14 pre-malignant).

RESULTS

On the validation cohort, the specificity of the CDOT test was 94 %, sensitivity was 90 % for participants with OSCC, and 84.2 % for participants with OPSCC. Similar classification results were observed among people in early stage (stages I & II) vs late stage (stages III & IV).

CONCLUSIONS

CDOT is a non-invasive test that can be easily administered in dentist offices, primary care centres and specialised cancer clinics for early detection of OPSCC and OSCC. This test, having received FDA's breakthrough designation for accelerated review, has the potential to enable early diagnosis, saving lives and significantly reducing healthcare expenditure.

Multisystem Inflammatory Syndrome in Children (MIS-C) Related to SARS-CoV-2 and 1-Year Follow-up

OBJECTIVE

To study the demographics, clinical profile, management, outcome and 1-y follow-up of children with multisystem inflammatory syndrome in children (MIS-C).

METHODS

This was a retrospective observational study of 54 Children satisfying the WHO MIS-C criteria admitted during the study period.

RESULTS

Fifty-four children were included in the study, median age was 5.5 (IQR 8.75), 68.5% were males. PICU admissions were 77%. Most involved organ was gastrointestinal (92%), followed by cardiovascular 85%, central nervous system (CNS) 74%, respiratory 72%, mucocutaneous 59%, and renal 31%, and hypotension was the presenting symptom in 43%. Coronary artery dilatation was seen in 1 (1.8%) child. All patients presented with more than three organs involvement. Raised procalcitonin was seen in 100%, raised BNP in 31.5%, low ejection fraction in 83.3%, and abnormal radiograph in 59%. All children were positive for anti-SARS-CoV-2 antibodies and negative for cultures. Methylprednisolone or intravenous immunoglobulin (IVIg) was used in 77%, mechanical ventilation in 18.5%, and inotropic support in 77%. Aspirin was used in 48% and low molecular weight heparin (LMWH) in 54%. The median stay in hospital was 7 d (IQR 2). There was 1 mortality (1.8%). On 7-d follow-up, 98% children had a normal echocardiography; on 6 mo and 1-y follow-up, all children had normal echocardiography.

CONCLUSION

MIS-C is an important complication of COVID-19 infection. Cardiac involvement resolves completely. Coronary artery involvement is not common.

Abstract 2240: Interception versus prevention in cancer screening: Results from the CRC-MAPS model

Purpose: This study examines the impact of detecting cancer (interception) versus adenomas and cancer (prevention + interception) on clinical outcomes for a hypothetical colorectal cancer (CRC) screening test or multicancer early detection (MCED) test that includes CRC.

Methods: CRC-MAPS™, a validated microsimulation model of the adenoma-carcinoma pathway that reproduced incidence reduction (IR) and mortality reduction (MR) consistent with CISNET models and a randomized controlled trial, was used to simulate perfect adherence to a hypothetical annual screening test among previously unscreened individuals free of diagnosed CRC. Four scenarios were examined: two cancer interception and two cancer prevention + interception. Individuals were screened from age 45 to 75. CRC IR and MR outcomes compared to no screening were aggregated from age 40 until death. Threshold analysis identified the ≥10mm adenoma sensitivity needed for a base case cancer interception test to yield CRC MR equivalent to a near-perfect cancer interception test (#2).

Results: The base case scenario (#1) resulted in 15.0% CRC IR and 34.2% MR compared to 14.7% CRC IR and 38.3% MR for the near-perfect interception scenario (#2). In the threshold analysis, a modified base case cancer interception test (#5) yielded MR equivalent to a near-perfect interception test (#2) when ≥10mm adenoma sensitivity was increased from 1% to 1.94%. Due to adenoma detection, the cancer prevention + interception scenarios (#3, #4) resulted in outcomes more than twice as favorable as either cancer interception scenario.

Conclusions: This analysis highlights that even small improvements in the detection of precancerous lesions for certain cancers (e.g., adenomas for CRC), which enable cancer prevention, can yield clinical benefits that meaningfully exceed those from tests that primarily detect cancer. Future studies will apply this approach to other cancers, such as ovarian and breast, to better understand the clinical utility of MCED tests.

Table. Clinical outcomes for cancer interception and cancer prevention + interception scenarios Scenario Specificity Adenoma Sensitivity CRC Sensitivity CRC IR CRC MR 1. Cancer Interception (base case) 99% 1-5mm: 1% 6-9mm: 1% ≥10mm: 1% 60% 15.0% 34.2% 2. Cancer Interception (near-perfect) 99% 1-5mm: 1% 6-9mm: 1% ≥10mm: 1% 99% 14.7% 38.3% 3. Cancer Prevention (with FIT-like adenoma sensitivity) + Interception 99% 1-5mm: 5% 6-9mm: 10% ≥10mm: 20% 60% 73.5% 79.1% 4. Cancer Prevention (with improved FIT-like adenoma sensitivity) + Interception 99% 1-5mm:10% 6-9mm: 20% ≥10mm: 30% 60% 82.8% 86.2% 5. Threshold analysis 99% 1-5mm: 1% 6-9mm: 1% ≥10mm: 1.94% 60% 20.3% 38.3%

Citation Format: Girish Putcha, Lauren N. Carroll, Signe Fransen, Tarun Chandra, Andrew Piscitello. Interception versus prevention in cancer screening: Results from the CRC-MAPS model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2240.

Interception versus prevention in cancer screening in a Medicare population: Results from the CRC-MAPS model

10546

Background: This study examines the impact of detecting cancer (interception) versus adenomas and cancer (prevention + interception) on clinical outcomes in a screen-naive Medicare cohort for a hypothetical colorectal cancer (CRC) screening test or a multicancer early detection (MCED) test that includes CRC. Methods: CRC-MAPS, a validated microsimulation model of the adenoma-carcinoma pathway that reproduced incidence reduction (IR) and mortality reduction (MR) consistent with CISNET models and a randomized controlled trial, was used to simulate perfect adherence to a hypothetical annual screening test among previously unscreened individuals free of diagnosed CRC. Four scenarios were examined: two cancer interception and two cancer prevention + interception. Individuals were screened from age 65 to 75. CRC IR and MR outcomes compared to no screening were aggregated from age 65 until death. Threshold analysis (#5) identified the ≥10mm adenoma sensitivity needed for a base-case cancer interception test (#1) to yield CRC MR equivalent to a near-perfect cancer interception test (#2). Results: The base-case interception scenario (#1) resulted in 5.6% CRC IR and 21.7% MR compared to 5.2% CRC IR and 25.9% MR for the near-perfect interception scenario (#2). The threshold analysis demonstrates that when the base-case interception scenario's ≥10mm adenoma sensitivity is increased from 1% to just 2.43% (#5), the resulting MR is equivalent to a near-perfect interception test. Accordingly, the cancer prevention + interception scenarios (#3, #4) resulted in CRC IR and MR outcomes 9.7-12.9x and 2.5-3.4x (respectively) as favorable as either cancer interception scenario due to adenoma detection. Conclusions: This analysis highlights that even small improvements in the detection of precancerous lesions for certain cancers (e.g., adenomas for CRC), which enable cancer prevention, can yield clinical benefits that meaningfully exceed those from tests that primarily detect cancer. Future studies will explore both benefits and burdens of different screening tests. Moreover, this approach will be applied to better understand the clinical utility of MCED tests. [Table: see text]

Evaluation of the Economic Benefit of Earlier Systemic Lupus Erythematosus (SLE) Diagnosis Using a Multivariate Assay Panel (MAP)

Objective

Diagnosis of systemic lupus erythematosus (SLE) made by standard diagnostic laboratory tests (SDLTs) has sensitivity and specificity of 83% and 76%, respectively. A multivariate assay panel (MAP) combining complement C4d activation products on erythrocytes and B cells with SDLTs yields a sensitivity and specificity of 80% and 86%, respectively, presumably enabling earlier SLE diagnosis at lower severity, with associated lower health care costs compared with SDLT diagnoses. We compared the payer budget impact of diagnosing SLE using MAP (incremental cost of $108) versus SDLTs.

Methods

We modeled a health plan of 1 million enrollees. SLE diagnosis among suspected patients was 9.2%. The MAP arm assumed 80%/20% of patients were tested with MAP/SDLTs, versus 100% tested with SDLTs in the SDLT arm. Prediagnosis direct costs were estimated from claims data, and postdiagnosis costs were obtained from the literature. Based on improved MAP performance, the assumed hazard ratio for diagnosis rate compared with SDLTs was 1.74 (71%, 87%, 90%, and 91% of patients who develop SLE are diagnosed in years 1 to 4 compared with 53%, 75%, 84%, and 88% of patients diagnosed with SDLTs).

Results

Total 4‐year pre‐ and postdiagnosis direct costs for patients with suspected SLE tested with MAP were $59 183 666 compared with $61 174 818 tested by SDLTs, with lower costs in the MAP arm due primarily to prediagnosis savings related to reduced hospital admissions.

Conclusion

Incorporating MAP into SLE diagnosis results in estimated 4‐year direct cost savings of $1 991 152 ($0.04 per member per month). By facilitating earlier diagnosis of SLE, MAP may enhance patient outcomes.

Cerebral venous sinus thrombosis as the initial presentation of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a hypercoagulable state due to a variety of mechanisms. Herein, we discuss the case of a 40-year-old gentleman who presented with cerebral venous sinus thrombosis (CVST) as the first manifestation of underlying SLE. On initial presentation, he did not endorse any other signs and symptoms to suggest the presence of an autoimmune condition. Work-up revealed an absence of antiphospholipid antibodies. Further evaluation uncovered the underlying etiology of the CVST as SLE-induced nephrotic syndrome. The existing literature on CVST suggests that there are only two other biopsy-proven cases of lupus nephritis leading to nephrotic range proteinuria as the etiology for CVST. Given the rarity of this presentation, there are no clearly delineated treatment strategies.

Flexible Bronchoscopic Removal of Foreign Bodies from Airway of Children: Single Center Experience Over 12 Years

OBJECTIVE

To report our experience of tracheobronchial foreign body removal in children using flexible bronchoscopy as the primary mode.

METHODS

Hospital records of tracheobronchial foreign body extractions between January, 2006 and January, 2018 were reviewed. Clinical presentations, radiological findings, location and types of tracheobronchial foreign bodies, types of bronchoscopes, complications and outcome of the procedures were analyzed.

RESULTS

283 extractions in children with median (range) age of 18 (5-168) months were reviewed. Extraction by flexible bronchoscope, using wire baskets or grasping forceps, was successful in 260 cases. No major complications were encountered. Mean (SD) time for the procedure was 31 (6.3) minutes.

CONCLUSION

Airway foreign bodies can safely be removed by flexible bronchoscopy with minimal complications. This procedure can be considered the primary mode for removal of airway foreign bodies by a trained and experienced person.

Cell bound complement activation products alone and in combination with low serum complement C3 or C4 have superior diagnostic performance in systemic lupus erythematosus

BACKGROUND

Cell-bound complement activation products (CB-CAPs) are sensitive and specific diagnostic markers of systemic lupus erythematosus (SLE). We compared the performance of CB-CAPs to low serum complement C3 or C4 in distinguishing SLE from other rheumatic diseases and healthy individuals.

METHODS

Adult subjects (n=1200) were enrolled from multiple academic centers, including SLE (498), healthy individuals (252) and subjects with other rheumatic diseases (450). Erythrocyte bound C4d [EC4d] and B-Lymphocyte bound C4d [BC4d] were quantitated using flow cytometry. Serum C3 and C4 levels were determined using immunoturbidimetry. Measurements included sensitivity, specificity, area under the curve (AUC) of the receiver operating characteristic curve (ROC) and Youden Index, for each marker as well as combinations.

RESULTS

Abnormal CB-CAPs status yielded 62% sensitivity with 88% specificity in distinguishing SLE from the group with other diseases compared to low C3/C4 status − 38% sensitivity, 93% specificity. Youden index was 0.492±0.03 for CB-CAPs compared to 0.313±0.03 for low C3/C4 (p&lt;0.01). AUC was higher with BC4d (0.72) than with EC4d (0.68; p&lt;0.01), low C3 (0.62; p&lt;0.01), low C4 (0.62; p&lt;0.01) and low C3 and/or C4 levels (0.66; p&lt;0.01).

The cumulative complement scoring system yielded higher AUC (0.81). A score with greater than 1 complement abnormality yielded 45% sensitivity and 98% specificity.

CONCLUSION

Our data suggests that CB-CAPs have greater diagnostic performance than low serum complement C3/C4. The combination of these complement abnormalities in a composite complement score is superior in distinguishing SLE from other rheumatic diseases and healthy individuals.

Stool DNA Analysis is Cost-Effective for Colorectal Cancer Surveillance in Patients With Ulcerative Colitis

BACKGROUND & AIMS

Patients with chronic ulcerative colitis are at increased risk for colorectal neoplasia (CRN). Surveillance by white-light endoscopy (WLE) or chromoendoscopy may reduce risk of CRN, but these strategies are underused. Analysis of DNA from stool samples (sDNA) can detect CRN with high levels of sensitivity, but it is not clear if this approach is cost-effective. We simulated these strategies for CRN detection to determine which approach is most cost-effective.

METHODS

We adapted a previously published Markov model to simulate the clinical course of chronic ulcerative colitis, the incidence of cancer or dysplasia, and costs and benefits of care with 4 surveillance strategies: (1) analysis of sDNA and diagnostic chromoendoscopy for patients with positive results, (2) analysis of sDNA with diagnostic WLE for patients with positive results, (3) chromoendoscopy with targeted collection of biopsies, or (4) WLE with random collection of biopsies. Costs were based on 2014 Medicare reimbursement. The primary outcome was the incremental cost-effectiveness ratio (incremental cost/incremental difference in quality-adjusted life-years) compared with no surveillance and a willingness-to-pay threshold of $50,000.

RESULTS

All strategies fell below the willingness-to-pay threshold at 2-year intervals. Incremental cost-effectiveness ratios were $16,362 per quality-adjusted life-year for sDNA analysis with diagnostic chromoendoscopy; $18,643 per quality-adjusted life-year for sDNA analysis with diagnostic WLE; $23,830 per quality-adjusted life-year for chromoendoscopy alone; and $27,907 per quality-adjusted life-year for WLE alone. In sensitivity analyses, sDNA analysis with diagnostic chromoendoscopy was more cost-effective than chromoendoscopy alone, up to a cost of $1135 per sDNA test. sDNA analysis remained cost-effective at all rates of compliance; when combined with diagnostic chromoendoscopy, this approach was preferred over chromoendoscopy alone, when the specificity of the sDNA test for CRN was >65%.

CONCLUSIONS

Based on a Markov model, surveillance for CRN is cost-effective for patients with chronic ulcerative colitis. Analysis of sDNA with chromoendoscopies for patients with positive results was more cost-effective than chromoendoscopy or WLE alone.

Novel therapy for insulin-dependent diabetes mellitus: infusion of in vitro-generated insulin-secreting cells

Insulin-dependent diabetes mellitus (IDDM) is a metabolic disease usually resulting from autoimmune-mediated β-cell destruction requiring lifetime exogenous insulin replacement. Mesenchymal stem cells (MSC) hold promising therapy. We present our experience of treating IDDM with co-infusion of in vitro autologous adipose tissue-derived MSC-differentiated insulin-secreting cells (ISC) with hematopoietic stem cells (HSC). This was an Institutional Review Board approved prospective non-randomized open-labeled clinical trial after informed consent from ten patients. ISC were differentiated from autologous adipose tissue-derived MSC and were infused with bone marrow-derived HSC in portal, thymic circulation by mini-laparotomy and in subcutaneous circulation. Patients were monitored for blood sugar levels, serum C-peptide levels, glycosylated hemoglobin (Hb1Ac) and glutamic acid decarboxylase (GAD) antibodies. Insulin administration was made on sliding scale with an objective of maintaining FBS < 150 mg/dL and PPBS around 200 mg/dL. Mean 3.34 mL cell inoculums with 5.25 × 10(4) cells/μL were infused. No untoward effects were observed. Over a mean follow-up of 31.71 months, mean serum C-peptide of 0.22 ng/mL before infusion had sustained rise of 0.92 ng/mL with decreased exogenous insulin requirement from 63.9 international units (IU)/day to 38.6 IU/day. Improvement in mean Hb1Ac was observed from 10.99 to 6.72%. Mean GAD antibodies were positive in all patients with mean of 331.10 IU/mL, which decreased to mean of 123 IU/mL. Co-infusion of autologous ISC with HSC represents a viable novel therapeutic option for IDDM.

Evaluation of carcinogenic potential of 17alpha-ethinylestradiol in a host-mediated in vivo/in vitro assay system

A host-mediated assay system for detection of the transforming activity of different chemical carcinogens on peritoneal macrophages has been previously established. Directly, as well as indirectly acting carcinogenic substances administered intraperitoneally to NMRI mice could be examined in this way. Resident macrophages were recovered by peritoneal lavage from treated and untreated mice and cultured in soft agar. After 5-6 days normal and transformed cells could be distinguished. By the use of this system an immortalized macrophage-like cell line was derived from the peritoneal cells of NMRI mice treated with 17alpha-ethinylestradiol. This cell line enabled us to perform additional investigations on the underlying molecular effects of 17alpha-ethinylestradiol, such as detection of the transformation specific polypeptides as surrogate markers for transformation. The investigation reported here describes the cell-transforming and oncogenic potential of 17alpha-ethinylestradiol.

Molecular interactions of the type 1 human immunodeficiency virus transregulatory protein Tat with N-methyl-d-aspartate receptor subunits

We investigated the effect of type 1 human immunodeficiency virus (HIV-1) regulatory protein Tat on N-methyl-d-aspartate (NMDA) receptors expressed in Xenopus oocytes by voltage-clamp recording and its role in NMDA-mediated neurotoxicity using cultured rat hippocampal neurons. Tat (0.01-1muM) potentiated NMDA-induced currents of recombinant NMDA receptors. However, in the presence of Zn(2+), the potentiating effect of Tat was much more pronounced, indicating an additional Zn(2+)-related effect on NMDA receptors. Consistently, Tat potentiated currents of the particularly Zn(2+)-sensitive NR1/NR2A NMDA receptor with a higher efficacy, whereas currents from a Zn(2+)-insensitive mutant were only marginally augmented. In addition, chemical-modified Tat, deficient for metal binding, did not reverse Zn(2+)-mediated inhibition of NMDA responses, demonstrating that Tat disinhibits NMDA receptors from Zn(2+)-mediated antagonism by complexing the cation. We therefore investigated the interplay of Tat and Zn(2+) in NMDA-mediated neurotoxicity using cultures of rat hippocampal neurons. Zn(2+) exhibited a prominent rescuing effect when added together with the excitotoxicant NMDA, which could be reverted by the Zn(2+)-chelator tricine. Similar to tricine, Tat enhanced NMDA-mediated neurotoxicity in the presence of neuroprotective Zn(2+) concentrations. Double-staining with antibodies against Tat and the NR1 subunit of the NMDA receptor revealed partial colocalization of the immunoreactivities in membrane patches of hippocampal neurons, supporting the idea of a direct interplay between Tat and glutamatergic transmission. We therefore propose that release of Zn(2+)-mediated inhibition of NMDA receptors by HIV-1 Tat contributes to the neurotoxic effect of glutamate and may participate in the pathogenesis of AIDS-associated dementia.

MRI features of tuberculosis of peripheral joints

The aim of this article is to present the magnetic resonance imaging (MRI) features of peripheral tubercular arthritis. The clinical presentation of peripheral tubercular arthritis is variable and simulates other chronic inflammatory arthritic disorders. MRI is a highly sensitive technique which demonstrates fine anatomical details and identifies the early changes of arthritis, which are not visible on radiographs. The MRI features of tubercular arthritis include synovitis, effusion, central and peripheral erosions, active and chronic pannus, abscess, bone chips and hypo-intense synovium. These imaging features in an appropriate clinical setting may help in the diagnosis of tubercular arthritis. Early diagnosis and treatment can effectively eliminate the long-term morbidity of joints affected by tuberculosis.

Inhibition of collagen glycation and crosslinking in vitro by methanolic extracts of Finger millet (Eleusine coracana) and Kodo millet (Paspalum scrobiculatum)

The present investigation was carried out to study the effects of methanolic extracts of Finger millet (Eleusine coracana) and Kodo millet (Paspalum scrobiculatum) on glycation and crosslinking of collagen. Tail tendons obtained from rats weighing 200-225 g were incubated with glucose (50 mM) and 3 mg of extracts of the above millets in methanol under physiological conditions of temperature and pH for 10 days. Early glycation was estimated by phenol-sulfuric acid method and the crosslinking was assessed by pepsin digestion, cyanogen bromide peptide map and viscosity measurements. Tendon collagen incubated with glucose (50 mM) showed 65% solubility on pepsin treatment; poor resolution of bands in the cyanogen bromide peptide map, and intrinsic viscosity of 0.84 dl/g. The collagen incubated with Finger millet and Kodo millet extracts inhibited glycation; 89% and 92% solubility in pepsin; good resolution of bands in the cyanogen bromide peptide map and intrinsic viscosity of 0.46 and 0.58 dl/g respectively. The study implicates the potential usefulness of the above millets in protection against glycation and crosslinking of collagen.

Giant-cell tumors of the patella

This study describes the clinical, radiographic, and histopathologic features, and discusses the management options of 11 cases of benign giant-cell tumors of the patella seen over 20 years. Fine needle aspiration cytology was a useful preoperative diagnostic tool. Ptellectomy and reconstruction of the extensor apparatus is the favored treatment option with curettage and bone grafting restricted to selected localized lesions.

Macrocyclic metalloenediynes of Cu(II) and Zn(II): a thermal reactivity comparison

The syntheses of tetradentate enediyne macrocycles with 24 (tact1:1)-, 26 (tact1:2)-, and 28 (tact2:2)-membered rings are described, along with their thermal reactivities and those of the corresponding Cu(II) (Cu(tact1:1), Cu(tact1:2)) and Zn(II) (Zn(tact1:1), Zn(tact1:2)) complexes. These enediyne macrocyclic ligands are not benzannulated and thus exhibit thermal Bergman cyclization temperatures near 200 degrees C by differential scanning calorimetry (DSC). Moreover, the synthetic route allows incorporation of additional carbon atoms into the macrocycles which increases their conformational flexibilities and lowers their Bergman cyclization temperatures. Specifically, as the size of the macrocycle increases, the temperatures at which these compounds undergo Bergman cyclization decrease by approximately 5 degrees C per additional carbon atom, leading to an overall decrease across the series of 19 degrees C. Incorporation of Cu(II) and Zn(II) into these macrocycles further reduces their cyclization temperatures relative to those of the free ligands. More uniquely, for Cu(tact1:1) and Zn(tact1:1), the observed cyclization temperatures vary by 27 degrees C with the Zn(II) complex lying to higher temperature (Cu(tact1:1) = 121 degrees C, (Zn(tact1:1) = 148 degrees C). As the macrocycle size is increased, the decrease in the Bergman cyclization temperatures observed for the free ligands does not systematically hold for the Cu(II) and Zn(II) derivatives. Rather, the Cu(II) complex exhibits the expected 9 degrees C decrease in the cyclization temperature (Cu(tact1:2) = 112 degrees C), whereas the temperature for the Zn(II) analogue increases by 15 degrees C (Zn(tact1:2) = 163 degrees C). From the X-ray crystal structure of the free ligand and the geometric structural preferences of the electronic configurations of Cu(II) and Zn(II), the higher cyclization temperatures for the Zn(II) complex with the larger ring size can be explained by a distortion of the macrocycle toward a more tetrahedral metal center geometry.

HES6 acts as a transcriptional repressor in myoblasts and can induce the myogenic differentiation program

HES6 is a novel member of the family of basic helix-loop-helix mammalian homologues of Drosophila Hairy and Enhancer of split. We have analyzed the biochemical and functional roles of HES6 in myoblasts. HES6 interacted with the corepressor transducin-like Enhancer of split 1 in yeast and mammalian cells through its WRPW COOH-terminal motif. HES6 repressed transcription from an N box-containing template and also when tethered to DNA through the GAL4 DNA binding domain. On N box-containing promoters, HES6 cooperated with HES1 to achieve maximal repression. An HES6-VP16 activation domain fusion protein activated the N box-containing reporter, confirming that HES6 bound the N box in muscle cells. The expression of HES6 was induced when myoblasts fused to become differentiated myotubes. Constitutive expression of HES6 in myoblasts inhibited expression of MyoR, a repressor of myogenesis, and induced differentiation, as evidenced by fusion into myotubes and expression of the muscle marker myosin heavy chain. Reciprocally, blocking endogenous HES6 function by using a WRPW-deleted dominant negative HES6 mutant led to increased expression of MyoR and completely blocked the muscle development program. Our results show that HES6 is an important regulator of myogenesis and suggest that MyoR is a target for HES6-dependent transcriptional repression.

Bronchial, alveolar, and vascular-induced anaphylaxis and irritant-induced cardiovascular and pulmonary responses

We examine the respiratory, bronchomotor, cardiac, and vascular responses to histamine and ragweed allergen delivered to the bronchi or alveoli compartments and the potential role of sensory nerves and reflexes mediating the histamine-induced responses. The masses of aerosols deposited in the bronchi and alveoli were quantitated using radioaerosol techniques. Activation of sensory nerves and/or histamine-induced mediator release were characterized by depositing nedocromil sodium aerosol prior to histamine challenge. The histamine-induced responses due to vagosympathetic transmission were determined by performing bilateral vagotomy. Both histamine and ragweed increased respiratory rate, ventilation, and bronchomotor tone whether deposited in the bronchial or alveolar regions. However, these responses were not elicited when histamine was administered intravenously. Precipitous allergen-induced decreases in heart rate and systolic and diastolic pressure were maximal 72 sec following ragweed deposition in alveolar regions of the lungs. Increases in respiratory rate were mediated via the vagus whether delivered to the bronchi, alveoli, or vasculature. Histamine-induced increases in respiratory rate and bronchomotor tone were attenuated by nedocromil. When histamine was delivered to the alveolar regions, increases in lung resistance appeared to be mediated primarily via the vagus and when delivered to the bronchial airways primarily by its action on smooth muscle or local reflexes. Histamine-induced hypotension and bradycardia appear to be mediated by the direct action of histamine on the cardiovascular system rather than through a vagally mediated reflex.

Immunohistochemical localization of transferrin in human breast cancer tissue

The present study was planned to detect the iron binding protein, transferrin (TR) in paraffin sections of the human breast tumors. The distribution of transferrin has been studied in 153 cases (63 benign lesions and 90 malignant tumors). The extent of staining reaction was determined by semiquantitative grading (weak, moderate and consistent). Positivity rate for transferrin was higher (92.2%) in malignant tumors as compared to benign breast lesions (28.5%) with significant p value (P = .0001) for both the groups. The intensity was variable in both the groups, being more intense in the malignant tumors. Tumors with higher grade of malignancy presented consistent positive staining along with the lymph nodes involved. The extent of immunoreactivity revealed a significant positive correlation with axillary lymph node status. However, no significant correlation was found with the age of the patients. Thus the study of transferrin in breast tumors besides being of prognostic significance helps in the further management of malignant lesions of the breast.

Disappearance of intramolecular stacking due to one-atom movement or increment of a 'propylene linker' in pyrazolo[3,4-d]pyrimidine-based flexible models

In the crystal structures of 4,6-dimethylthio-1-[3-(4, 6-dimethylthio-2H-pyrazolo[3, 4-d]pyrimidin-2-yl)propyl]-1H-pyrazolo[3,4-d]pyrimidine, C(17)H(20)N(8)S(4), and 1-[4-(4-methoxy-6-methylthio-1H-pyrazolo[3, 4-d]pyrimidin-1-yl)butyl]-5-methyl-6-methylthio-4, 5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one, C(18)H(22)N(8)O(2)S(2), only intermolecular stacking due to aromatic pi-pi interactions between pyrazolo[3,4-d]pyrimidinerings is present.

Immunohistochemical localization of transferrin in human breast cancer tissue

The present study was planned to detect the iron binding protein, transferrin (TR) in paraffin sections of the human breast tumors. The distribution of transferrin has been studied in 153 cases (63 benign lesions and 90 malignant tumors). The extent of staining reaction was determined by semiquantitative grading (weak, moderate and consistent). Positivity rate for transferrin was higher (92.2%) in malignant tumors as compared to benign breast lesions (28.5%) with significant p value (p = 0.0001) for both the groups. The intensity was variable in both the groups, being more intense in the malignant tumors. Tumors with higher grade of malignancy presented consistent positive staining along with the lymph nodes involved. The extent of immunoreactivity revealed a significant positive correlation with axillary lymph node status. However, no significant correlation was found with the age of the patients. Thus the study of transferrin in breast tumors besides being of prognostic significance helps in the further management of malignant lesions of the breast.

Primary intrapulmonary teratoma presenting as pyothorax

A female patient presented with empyema thoracis and was planned for decortication. Peroperatively a cystic mass was found in the left lower lobe which was resected and diagnosed as a case of teratoma of lung on histopathological examination. This unusual case of primary intrapulmonary teratoma is being reported here.

Cytopathology and AgNOR counts in fine-needle aspiration cytology smears of thyroid lesions

The object of the present work is to study the cytomorphological features and the value of silver colloidal staining method in distinguishing the non-neoplastic, benign, and malignant neoplasm in fine-needle aspiration cytology (FNAC) smears of thyroid nodules. One hundred forty histologically confirmed aspirated samples of thyroid lesions were studied and classified cytologically. These smears were stained for AgNOR counts. The number and location of AgNOR dots as well as clusters in nuclei were studied by two different observers independently. Lower AgNOR counts were recorded in cases of thyroiditis (1.375 +/- 0.414), whereas follicular carcinoma had a higher number of AgNOR counts (5.04 +/- 0.52). The clusters of AgNOR dots were centrally located in colloid goitre, but no cluster arrangement was observed in cases of carcinomas. Increased nuclear size, nucleoli, and chromocentres were helpful in the diagnosis of follicular carcinoma. AgNOR counting cannot be reliably used on an individual case basis to differentiate adenoma from carcinoma. Therefore, AgNOR study in thyroid lesions can be used as an additional diagnostic method with cytomorphological features to differentiate benign and malignant follicular neoplasms.

Statistical significance of AgNOR counts in FNAC smears and corresponding histopathological sections

The object of the present study was to determine the statistical significance of AgNOR counts in fine needle aspiration cytology (FNAC) smears and corresponding paraffin sections by using an one step silver colloidal staining method. Ninety five cases (31 benign and 64 malignant) were taken and a correlation between smears and sections was studied by two different observers. The total number of mean (SD) AgNOR counts was significantly higher in FNAC smears in benign (3.081 +/- .753) and malignant (7.101 +/- 1.544) neoplasms in comparison to paraffin sections in the same group of cases. FNAC smears had a cut off point 4 with proliferation index 1% in benign tumors and 97.5% in malignant tumors. Sections had an overlapping of AgNOR counts (5-7) with proliferation index 3.8 and 82% for benign and malignant groups respectively. The difference in the coefficient of variations was 3% in benign group and 2% in malignant group in FNAC smears while sections had 6 and 8% difference in the coefficient of variations. Smears present a superior staining and accurate number of AgNOR dots in nucleus as compared to paraffin sections. Therefore the results suggest that AgNOR technique can be successfully used in FNAC smears in comparison to paraffin sections to differentiate benign and malignant tumors in routine laboratory diagnosis.

Predictive value of fine needle aspiration cytology of bone lesions

OBJECTIVE

To determine the predictive value of fine needle aspiration cytology (FNAC) of bone lesions.

STUDY DESIGN

The study consisted of data retrieval on 200 cases of bone lesions and their cytohistopathologic correlation to assess the diagnostic efficacy of FNAC in these cases, considering histopathology as the gold standard. The diagnostic indices were calculated by a decision matrix comparison.

RESULTS

On cytohistopathologic correlation of 200 cases, 106 (53.0%) were malignant bone tumors (MBT): 97 primary and 9 metastatic; and 76 were benign bone lesions (BBL), 58 neoplastic (29%) and 18 nonneoplastic (9%). The aspirated material was adequate in 181 cases, whereas in 18 cases cytohistopathologic examination revealed no bony lesion. Thus, there were 163 evaluable cases, of which the specific morphologic diagnoses on FNAC were possible in 141 cases (86.5%), with a solitary false positive and 8 false negatives. The percentage of inadequate aspirates was more with BBL (13.2%) than MBT (8.5%). The overall diagnostic accuracy and sensitivity of bone lesions were 95.0%, whereas specificity, positive predictive value (PPV) and negative predictive value (NPV) were 94.7%, 99.4% and 69.2%, respectively. The sensitivity of FNAC was better (95.8%) with MBT as compared to BBL (91.7%), whereas specificity and PPV were almost equal (98.8% and 99.2%) in both cases. The NPV in cases of BBL was higher (97.8%) than in MBT (95.2%). These diagnostic indices were calculated excluding the inadequate cases.

CONCLUSION

High PPV and NPV indicate the reliability of FNAC for the diagnosis of bone lesions.

Diagnostic relevance of silver stained nucleolar organizer region (AgNORs) in benign and malignant breast lesions

The present study is planned to assess the diagnostic relevance of silver stained nucleolar organizer regions (NORs) in discriminating benign from malignant lesions of the breast and to ascertain the interobserver variability in the enumeration of AgNOR counts. Forty four specimens of benign and malignant breast tissues were studied and mean number of silver stained nucleolar organizer regions (MNORA) have been counted in paraffin sections. Malignant lesions have a higher number of MNORA than benign lesions. These results also showed correlation between the AgNOR counts and size of the tumor, axillary lymph node status and age of the patient. Our results also indicate a close agreement between the two observers with limits of agreement. However, AgNOR counts are of little diagnostic importance since a broad zone of overlap exists between benign and malignant breast diseases despite significant higher mean counts in malignant lesions. AgNOR sequence could perhaps be of use to differentiate those two histological indistinguishable lesions. The tumor size and axillary lymph node involvement suggested to its prognostic significance also. Interobserver agreement further suggests the utility of AgNOR counts as diagnostic or prognostic discriminants in breast malignancies.

Antiallergic activity of alkyl substituted pyrazolo[3, 4-d]pyrimidine (compound 88-765)

Compound 88-765 (4-amino-6-methylthio-1-(2', 2'-diethoxyethyl)-1 H-pyrazolo[3, 4-d]pyrimidine) has shown potent antiallergic activity in experimental models. The compound inhibited the passive cutaneous anaphylaxis (PCA) reaction in rats in dose-dependent manner (5-100 mg/kg, po) by 47 to 87%. In mice it inhibited PCA by 78% at 50 mg/kg, po. It also inhibited mast cell degranulation of normal and passively sensitised rats induced by compound 48/80 and egg albumin, respectively. These effects of Compound 88-765 were comparable with that of disodium cromoglycate (DSCG). The results suggest that compound 88-765 possesses potent antiallergic activity.

Stationary and nonstationary correlation-frequency analysis of heterodyne mode laser light scattering: magnitude and periodicity of canine tracheal ciliary beat frequency in vivo

Stationary and nonstationary correlation-frequency analysis of heterodyne laser light scattering were utilized to make automated, on-line, objective measurements of tracheal ciliary beat frequency (CBF) in intact, anesthetized canines. The stationary correlation-frequency analysis laser light-scattering technique was used to assess the magnitude of the CBF stimulatory responses induced by aerosolized 10(-5) M fenoterol (sympathomimetic), and 10(-8) M and 10(-6) M methacholine (parasympathomimetic) delivered to the whole lungs of eight barbiturate-anesthetized beagles. The nonstationary correlation-frequency analysis laser light-scattering technique was used to measure the effect on tracheal CBF of increasing the cytosolic calcium ion concentration with a calcium ionophore, A23187. Aerosolized A23187 was delivered to the isolated tracheal lumens of eight beagle dogs in cumulative doses ranging from 10(-9)M to 10(-6) M. Administration of the ionophore synchronized the CBF with a period of 5.3 min. Dose dependencies were observed in both the time to the peak CBF stimulation and the magnitude of the stimulatory response. The magnitude of CBF stimulation was inhibited by prior administration of aerosolized nifedipine (2 mg/ml), a voltage-operated calcium channel blocker. The A23187-induced modulation period of tracheal CBF, was unchanged by nifedipine. These are the first data to demonstrate that the magnitude and periodicity of CBF are two independent coupled processes. The cooperativity of these two processes could be determined in the effectiveness of mucociliary transport.

A pore transport model for pulmonary alveolar epithelium

Hydrodynamic heteropore flow models for transport of solutes across alveolar epithelial tissue have been developed. A two-size cylindrical pore model and a similar parallel-plate model were formulated, tested and used to predict effective pore sizes from literature data on transport in bullfrog, canine and rat lungs. The best fit equivalent pore-size estimates were obtained using a modified, nonlinear least squares procedure, with alveolar surface area to volume ratio (S/V) and small-pore area fraction of total pore area as parameters. Small-pore and large-pore width estimates of 4 nm (84% of total flow area) and 10 nm, respectively, with an average deviation of 20% from experimentally derived permeabilities were obtained from the bullfrog alveolar epithelium parallel-plate pore model (13 solutes, diameters 0.3 to 2.8 nm). The equivalent cylindrical pore model diameter estimates were 5 nm and 10 nm, with small-pore area fraction and percentage deviations similar to the parallel-plate model estimates. Eighty-eight percent of the bulk water driven by a sucrose osmotic gradient was predicted to be transported through the small pores. The rat alveolus parallel-plate pore model (6 solutes) yielded small-pore and large-pore widths of 0.4 nm and 50 nm, respectively. Clearance rate-constant data for dextran macromolecules (3,000 to 250,000 Daltons), using a single parallel-plate pore model, resulted in a pore width estimate of 98 nm for canine alveoli with an average deviation of the predicted rate constants of 18% from literature experimental values. In all cases tested, the parallel-plate pore model predicted lower small-pore size estimates than did the cylindrical pore model, and both models had appreciably smaller percentage deviations from experimental data than previous models.

Work of adhesion of respiratory tract mucus

A method was devised to measure the work of adhesion (WA) to a substrate of mucus, a viscoelastic gel, from the measured contact angle of glycerol on a mucus substrate and the known physical properties of a Teflon surface. Fifteen sputum samples from cystic fibrosis (CF) patients were compared with 25 mucus samples from canine tracheal pouches (CP), studied in the hydrated and partially dehydrated states. Apparent viscosity (eta A) and recoverable shear strain (SR) were measured by fluxgate magnetometry, and water content was inferred from vapor pressure osmometry. Na+, K+, and Ca2+ concentrations were measured with specific ion electrodes and Cl- with a chloridimeter. The Cl- concentration of the CP mucus was inversely proportional to its osmolality, and the Cl- concentration of the CP mucus was 102.5 +/- 1.6 meq/l compared with 55.6 +/- 2.5 meq/l for CF sputum. When CP mucus osmolality was increased from 316.0 +/- 5.5 to 430.0 +/- 7.5 mosmol/kg, WA increased from 25.1 +/- 1.8 to 31.1 +/- 1.2 ergs/cm2 and eta A increased from 391 +/- 55 to 622 +/- 121 P, respectively. CF sputum WA was 30.2 +/- 0.6 ergs/cm2, eta A was 1,110 +/- 316 P, and osmolality was 466.0 +/- 14.0 mosmol/kg. The increased WA and eta A of mucus in CF patients may thus be dependent on the hydration of mucus, which is related to the documented Cl- transport defect.

The effect of diacylglycerols on fibronectin release and its reversal by retinoic acid in cell culture

Previous work from our laboratory showed that tumor promoters such as phorbol ester (TPA) stimulated the release of fibronectin (FN) from the surface of several cell types in culture, and that this stimulation was counteracted by retinoic acid. Diacylglycerols (DAGs) are the endogenous ligands of the TPA receptor and can activate and translocate protein kinase C (PKC) in a manner similar to TPA. To show that the release of FN is related to activation of PKC, we tested the action of DAGs on FN release from human lung fibroblasts and its counteraction by retinoic acid. We found that DAGs stimulated the release of FN in a concentration- and time-dependent manner. The stimulation of the release of FN correlated with the translocation-activation of PKC by DAG. Retinoic acid reversed the action of DAG with respect to stimulation of FN release and inhibited this release even in the absence of DAG. These results suggest that the release of FN is in some way related to translocation-activation of PKC.

Haptoglobin phenotypes in diabetes mellitus and diabetic retinopathy

An analysis of haptoglobin (HP) phenotypes in 81 cases of diabetes mellitus (DM) without retinopathy and 122 cases with diabetic retinopathy (DR) were studied in relation to 180 normal and healthy controls matched for age and sex. A significant decrease in HP 2-1 frequency was found, suggesting protection for heterozygotes in both DM and DR (with a relative risk of about 0.31). As an acute-phase reactant HP may be functionally involved in the etiology of DM and DR, which are associated with immunologic and inflammatory processes, respectively. No significant differences were found with respect to sex, age at onset, duration of DR, types of DM and DR, and family history.

The anti-inflammatory activity of Enicostemma littorale and Mollugo cerviana

The anti-inflammatory activity of E. littorale and M. cerviana was assessed by carrageenan-induced inflammation and cotton pellet granuloma method in rats. E. littorale and M. cerviana exerted 54 and 26% anti-inflammatory activity for a dose of 100 mg/100 g body wt, respectively, in carrageenan-induced acute inflammation. In chronic inflammation of cotton pellet granuloma, E. littorale and M. cerviana exerted 30 and 46% anti-inflammatory activity at the above dosage, respectively. The optimal dose for these drugs was determined in carrageenan inflammation. The effect of the alcoholic extract of these drugs on human erythrocyte membrane stabilization and inhibition of cobra venom phospholipase A2 was studied in vitro and the drugs were found to be effective. Further, these drugs were found to inhibit the levels of lipid peroxides, acid phosphatase, and gamma-glutamyl transpeptidase activity in the exudate of cotton pellet granuloma. The effects were compared with those of standard anti-inflammatory drug, hydrocortisone. A possible mode of action of these drugs is suggested.

Biochemical modes of action of Cassia occidentalis and Cardiospermum halicacabum in inflammation

The anti-inflammatory activity of Cassia occidentalis leaf powder and an ethanol extract of Cardiospermum halicacabum aerial parts were assayed in male albino rats using carrageenan-induced rat paw edema. C. occidentalis was maximally active at a dose of 2000 mg/kg, while the C. halicacabum extract was maximally effective at a dose of 500 mg/kg. In the cotton pellet granuloma assay, these drugs were able to suppress the transudative, exudative and proliferative components of chronic inflammation. Further, these drugs were able to lower the lipid peroxide content and gamma-glutamyl transpeptidase and phospholipase A2 activity in the exudate of cotton pellet granuloma. The increased alkaline phosphatase activity and decreased A/G ratio of plasma in cotton pellet granulomatous rats were normalized after treatment with these drugs. C. occidentalis powder and C. halicacabum extract were able to stabilize the human erythrocyte membrane against hypotonicity-induced lysis. It is likely that these drugs may exert their anti-inflammatory activity by inhibition of phospholipase A2, resulting in the reduced availability of arachidonic acid, a precursor of prostaglandin biosynthesis, and/or by stabilization of the lysosomal membrane system.

A new receipt for liver injury

A new receipe consisting of Phyllanthus fraternus Webster, Eclipta alba and curcumin was prepared. The efficacy of this preparation was tested in carbontetrachloride (CCl(4)) induced fatty liver model in rats. This preparation was able to normalize the level of lipids accumulating in liver due to CCl(4) injury and it was also able to bring down elevated levels of serum bilirubin. Further, the decreased levels of serum triglycerides, pre B-lipoproteins and cholesterol in CCl(4) liver injured rats was raised after treatment with new preparation. Further, the decreased level of liver glycogen was also normalized. From these results, it can be inferred that the new receipe is able to offer protection against the liver injury caused by CCl(4) injection.

Complete sequence of the cDNA for human alpha 1-antitrypsin and the gene for the S variant

A 1434 base pair human liver cDNA coding for the entire alpha 1-antitrypsin protein has been isolated and sequenced. Translation of the coding region into amino acids reveals a precursor molecule which contains a 24 amino acid signal peptide and 394 amino acids present in the mature polypeptide chain. The human gene for the S variant of alpha 1-antitrypsin has also been subcloned and sequenced. The gene is composed of 10226 nucleotide bases and is approximately equimolar for all 4 nucleotides. The gene contains four intervening sequences (introns) and 5' and 3' noncoding regions which are 54 and 79 nucleotides in length, respectively. A 5.3-kilobase intron exists in the 5' noncoding region and contains a 143 amino acid open reading frame, an Alu family sequence, and a pseudo transcription initiation region. No significant differences in base composition are seen between the introns and those regions corresponding to coding regions of the corresponding mRNA (exons). A sequence of 1951 nucleotides flanking the 5' end of the gene has also been determined and contains a "TATA" box sequence (TTAAA-TA) 21 nucleotides upstream from the proposed transcription start site. Comparison of the gene sequence with the cDNA sequence reveals a single base substitution (A----T), which results in a Glu----Val substitution at position 264 in the S variant protein. The position and size of introns, the overall base composition, and the codon preference for the alpha 1-anti-trypsin gene differ from those for the chicken ovalbumin gene even though the two proteins belong to a common protein family, as judged by amino acid sequence homology.

Genetic mapping of the structural gene for antithrombin III to human chromosome 1

Using a purified cDNA probe of human antithrombin III (AT3) gene and a series of human/Chinese hamster cell hybrids, we established the chromosomal location of the structural gene for AT3 in human chromosome 1 by Southern blot analysis.

Construction and identification of mouse amelogenin cDNA clones

The determination of the biochemical phenotype of tooth epithelium requires specification by the dental mesenchyme. This is a general feature of epithelial-mesenchymal interaction in a number of different epidermal organ systems (e.g., salivary gland, mammary gland, feather, skin, and hair morphogenesis). To investigate these developmental processes, we have identified a cDNA clone representing the major group of gene products associated with enamel extracellular matrix formation. The mRNAs for mouse amelogenins, representing approximately equal to 90% of the total enamel proteins, have been isolated and partially characterized by specific immunoprecipitation. The poly(A)-containing RNAs were used for the synthesis and cloning of the mouse amelogenin cDNA. Recombinant plasmids containing amelogenin cDNA sequences were identified by differential hybridization, hybrid-selected translation, and blot hybridization analyses. A cloned sequence was used to identify the expression of amelogenins during tooth development. The mouse cDNA sequence hybridized to genomic mouse and human DNAs. This amelogenin cDNA probe now enables molecular investigations of a number of classical problems in developmental biology.

Cloned human phenylalanine hydroxylase gene allows prenatal diagnosis and carrier detection of classical phenylketonuria

The human gene for the hepatic enzyme phenylalanine hydroxylase has been cloned and used to analyse the phenylalanine hydroxylase locus in the human genome. The detection of polymorphisms in this locus by several restriction enzymes has allowed feasibility studies of prenatal diagnosis of classical phenylketonuria and identification of carriers of the trait. Results indicate that these services could be provided for up to 75% of all families with phenylketonuric children in the general Caucasian population.

Sequence homology between human alpha 1-antichymotrypsin, alpha 1-antitrypsin, and antithrombin III

alpha 1-Antichymotrypsin mRNA was isolated by specific polysome immunoprecipitation from turpentine-treated baboon liver. The highly enriched mRNA was used for synthesis and cloning of the corresponding cDNA. Baboon alpha 1-antichymotrypsin cDNA clones were identified by hybrid-selected translation, and the insert DNA fragment from one of the putative clones was used as a probe to screen a human liver cDNA library comprised of 40 000 independent transformants. One of the human cDNA clones was unambiguously identified to contain alpha 1-antichymotrypsin DNA sequences by comparison of its 5'-terminal nucleotide sequence with the N-terminal amino acid sequence of the protein. This cDNA clone, designated phACT235, contains 1524 base pairs of human DNA, which was sequenced in its entirety. The inserted DNA codes for a 25 amino acid signal peptide sequence and the entire mature alpha 1-antichymotrypsin of 408 amino acid residues. Comparison of the amino acid sequence of alpha 1-antichymotrypsin with that of the human alpha 1-antitrypsin has revealed a homology level similar to that between chymotrypsin and trypsin.

Isolation and sequence characterization of a cDNA clone of human antithrombin III

A human liver cDNA library was constructed by using poly(A)-containing RNA isolated from a human liver biopsy specimen. This library is comprised of 40,000 independent transformants with an average inserted DNA length of 1,200 base pairs. By using the previously cloned baboon antithrombin III cDNA as a specific hybridization probe, greater than 30 human antithrombin III cDNA clones were identified from this library. The clone with the longest DNA insert was selected for sequence analysis. This antithrombin III cDNA clone contains 1,479 base pairs of inserted human DNA and was designated phATIII 113. It contains DNA sequences that code for a signal peptide and the entire mature antithrombin III protein which is comprised of 432 amino acid residues.

Identification of multiple species of calmodulin messenger RNA using a full length complementary DNA

Poly(A) RNA from eel electroplax was used to construct a full length cDNA complementary to calmodulin (CaM) mRNA which was cloned in the PstI site of pBR322 DNA. Recombinant plasmids containing sequences complementary to CaM mRNA were identified by hybridization using a 32P-labeled CaM cDNA (pCM109). Nucleotide sequence analysis reveals that the clone from the plasmid pCM116 contains a 5' nontranslated region of 26 nucleotides, the entire coding region, and a 3' nontranslated region of 408 nucleotides. The amino acid sequence deduced from the nucleotide sequence is similar to those previously reported for CaM from other species. Comparison between the nucleotide sequence of the functional domains of the protein shows extensive homology between all four domains. pCM116 was utilized to determine and compare the populations of RNA present in different tissues. In eel electroplax, three species of cytoplasmic RNAs at 820, 1100, and 2000 nucleotides hybridize to the cDNA probe. The nucleus contains an additional CaM RNA molecule of 5500 nucleotides which may represent a primary transcript of the calmodulin gene. Sequence analysis of the 3' noncoding region of pCM116 reveals 3 possible polyadenylation sites (AATAAA) at positions 573, 580, and 855. The mRNA of 820 nucleotides was derived by polyadenylation at the first site whereas the mRNA of 1100 nucleotides was derived by poly(A) addition at position 855. These data are compatible with the idea that at least 2 of the 3 CaM mRNAs in eel electroplax tissue are derived from a single nuclear transcript by differential polyadenylation during processing.