Quantifying misdiagnosis rates from cross-calibration biases and precision errors in dual-energy X-ray absorptiometry of the femoral neck

BACKGROUND

Dual-energy X-ray absorptiometry (DXA) is an exam that measures areal bone mineral density (aBMD) and is regularly used to diagnose and monitor osteoporosis. Except for exam quality issues such as operator error, the quantitative results of an exam are not modified by a radiologist or other physician. DXA cross-calibration errors can shift diagnoses, conceivably leading to alternate intervention decisions and patient outcomes.

PURPOSE

After identifying and correcting a cross-calibration bias of 3.8% in our two DXA scanners' aBMD measurements, we investigated misdiagnosis rates for given cross-calibration errors in a single patient cohort to determine the impact on patient care and the value of cross-calibration quality control.

METHODS

The studied cohort was 8012 patients of all ages and sexes with femoral neck exams that were scanned on a single DXA unit from October 1, 2018 to March 31, 2021. There were six subcohorts delineated by age and sex, three female groups and three male groups. Data reporting focused on the highest risk subcohort of 2840 females aged 65 or older. The DXA unit had no calibration changes during that time. Only one femoral neck-left or right-was randomly chosen for analysis. Patients with multiple qualifying exams within the time interval had one exam randomly chosen. The proof-of-principle simulation shifted the aBMD values within a range of ±10%, ±8%, ±6%, ±4%, ±3.5%, ±3%, ±2.5%, ±2%, ±1.5%, ±1%, ±0.5%, and 0 (no shift); the cross-calibration shifts were informed by published results and institutional experience. Measurement precision was modeled by randomly sampling a Gaussian distribution characterized by the worst acceptable least significant change (LSC) of 6.9%, with 100 000 samplings for each patient. T-scores were recalculated from the shifted aBMD values, followed by reassigned diagnoses from the World Health Organization's T-score-based scheme.

RESULTS

The unshifted original subcohort of women aged 65 and older had 599 normal diagnoses (21.1% of the cohort), 1784 osteopenia diagnoses (62.8%), and 455 osteoporosis diagnoses (16.1%). Osteoporosis diagnosis rates were highly sensitive to aBMD shifts. At the extrema, a -10% aBMD shift led to +161% osteoporosis cases, and a +10% aBMD shift led to -64.5% osteoporosis cases. Within the more plausible ±4% aBMD error range, the osteoporosis diagnosis rate changed -10.5% per +1% aBMD shift as indicated by linear regression (R²  = 0.98). Except for the men aged 49 years and younger subcohort, the total cohort and five subcohorts had fit line slopes ranging between -9.7% and -12.1% with R² ≥ 0.98. Cross-calibration bias had greater influence for diagnosis count rates compared to measurement precision, that is, LSC.

CONCLUSIONS

These results quantify the degree of misdiagnosis that can occur in a clinically relevant cohort due to cross-calibration bias. In medical practices where patients may be scanned on more than one DXA unit, ensuring cross-calibration quality is a critical and high-value quality control task with direct impact on patient diagnosis and treatment course. The clinical impact and incidence of poor DXA quality control practices, and cross-calibration in particular, should be studied further.

Assessment of gait and posture characteristics using a smartphone wearable system for persons with osteoporosis with and without falls

We used smartphone technology to differentiate the gait characteristics of older adults with osteoporosis with falls from those without falls. We assessed gait mannerism and obtained activities of daily living (ADLs) with wearable sensor systems (smartphones and inertial measurement units [IMUs]) to identify fall-risk characteristics. We recruited 49 persons with osteoporosis: 14 who had a fall within a year before recruitment and 35 without falls. IMU sensor signals were sampled at 50 Hz using a customized smartphone app (Lockhart Monitor) attached at the pelvic region. Longitudinal data was collected using MoveMonitor+ (DynaPort) IMU over three consecutive days. Given the close association between serum calcium, albumin, PTH, Vitamin D, and musculoskeletal health, we compared these markers in individuals with history of falls as compared to nonfallers. For the biochemical parameters fall group had significantly lower calcium (P = 0.01*) and albumin (P = 0.05*) and higher parathyroid hormone levels (P = 0.002**) than nonfall group. In addition, persons with falls had higher sway area (P = 0.031*), lower dynamic stability (P < 0.001***), gait velocity (P = 0.012*), and were less able to perform ADLs (P = 0.002**). Thus, persons with osteoporosis with a history of falls can be differentiated by using dynamic real-time measurements that can be easily captured by a smartphone app, thus avoiding traditional postural sway and gait measures that require individuals to be tested in a laboratory setting.

Vitamin D deficiency, parathyroid hormone levels, and bone disease among patients with end-stage liver disease and normal serum creatinine awaiting liver transplantation

Vitamin D deficiency is common among patients with end-stage liver disease (ESLD). The primary aim of our study was to assess the prevalence of vitamin D deficiency, secondary hyperparathyroidism, and bone disease in patients with ESLD awaiting LT.

METHODS

We retrospectively studied 190 patients at our center. Serum total 25-hydroxyvitamin D (25-OH D), parathyroid hormone (PTH), calcium, and bone mineral analysis (BMA) were recorded. Standard World Health Organization (WHO) criteria were used to diagnose osteopenia/osteoporosis. Only patients with normal serum creatinine were analyzed.

RESULTS

Thirty-two of 190 patients were excluded from the final analysis (missing serum total 25-OH D levels in three patients and elevated serum creatinine, 29 patients). 105 of 158 (66.4%) evaluable patients had 25-OH D levels <25 ng/mL. Patients included in the analysis (n = 158) were divided according to serum total 25-OH D levels: 0-10 ng/mL (n = 23), 11-20 ng/mL (n = 64), and >20 ng/mL (n = 71). There were no significant differences in mean serum PTH and corrected calcium levels among the three subgroups. Only three patients had elevated serum PTH. Patients with total 25-OH D ≤ 10 ng/mL had higher model for end-stage liver disease (MELD) scores vs. those with 25-OH D > 20 ng/mL (13.3 ± 3, range 8-21, vs. 11.9 ± 3.4, range 6-29, p = 0.004). Irrespective of vitamin D status, bone disease was present in 64.6% of patients.

CONCLUSION

Low vitamin D levels and bone disease are common among patients with ESLD awaiting LT. Despite a high prevalence of low serum total 25-OH D, our cohort maintained normal corrected calcium levels and did not develop secondary hyperparathyroidism. We propose that free serum 25-OH D and vitamin D-binding protein may be necessary to accurately establish the diagnosis of vitamin D deficiency in the setting of ESLD. Additional studies are needed to further define mechanisms of bone disease in patients with ESLD.

Clinical and bone density outcomes of tumor-induced osteomalacia after treatment

OBJECTIVE

To report the outcomes of tumor-induced osteomalacia after treatment, particularly related to recovery of bone mass.

METHODS

We review the clinical course of a 61-year-old man extremely debilitated from multiple fractures and neuromuscular weakness due to tumor-induced osteomalacia and report the changes in biochemical markers and bone density after removal of the causative neoplasm.

RESULTS

At the time of diagnosis, the patient's serum phosphorus and 1,25 dihydroxyvitamin D levels were depressed, and his fibroblast growth factor-23 level was markedly elevated. These values normalized 2 days after surgery and remained within their respective reference ranges 4 and 12 months after resection of a mesenchymal tumor. Lumbar bone density values (T-scores) were 0.445 g/cm2 (-5.9) preoperatively, 0.939 g/cm2 (-1.4) 4 months after surgery, and 1.152 g/cm2 (0.7) 12 months after surgery. Left femoral neck values at the same time points were 0.525 g/cm2 (-3.0), 1.035 g/cm2 (-0.8), and 1.184 g/cm2 (1.9). Ultra-distal radius values at the same time points were 0.128 g/cm2 (-7.0), 0.191 g/cm2 (-5.9), and 0.259 g/cm2 (-4.8). In addition, he recovered neuromuscular function and was able to leave his wheelchair.

CONCLUSION

Tumor-induced osteomalacia can be an extremely debilitating disease. With successful localization, identification, and resection of the neoplasm, bone mass and physical function can recover.

Diabetes care in hospitalized noncritically ill patients: More evidence for clinical inertia and negative therapeutic momentum

BACKGROUND

Little is known about management of hyperglycemia in inpatients.

OBJECTIVE

To gain insight into caring for hospitalized patients with hyperglycemia.

DESIGN

Retrospective analysis.

SETTING

Teaching hospital.

PATIENTS

Data on all patients discharged between January 1, 2001, and December 31, 2004 with a diagnosis of diabetes or hyperglycemia were extracted and linked to laboratory and pharmacy databases. Only the data on patients who did not require intensive care and who were hospitalized for at least 3 days were analyzed.

MEASUREMENTS

Average bedside glucose during the first and last 24 hours of hospital stay and for the entire length of stay; assessment of changes in insulin regimen and dose.

RESULTS

The average age of patients included in the study (n = 2916) was 69 years. Fifty-seven percent of the patients were men, 90% were white, and average length of stay was 5.7 days. More than 20% of the patients had evidence of sustained hyperglycemia. Forty-two percent of the patients who showed poor control of glycemia (glucose > 200 mg/dL) during the first 24 hours were discharged in poor control. The frequency of hypoglycemia was low (only 2.2 of 100 measurements per person) compared with hyperglycemia (25.5 of 100 measurements per person). Most patients (72%) received insulin during hospitalization, but there was high use of short-acting insulin and less than optimal intensification of therapy (clinical inertia); many patients had insulin therapy decreased despite persistent hyperglycemia (negative therapeutic momentum).

CONCLUSIONS

Glycemic control in the hospital was frequently poor, and there was suboptimal use of insulin, even among patients with sustained hyperglycemia. Educational programs directed at practitioners should focus on the importance of inpatient glucose control and provide guidelines on how and when to change therapy.

Diabetes care in the hospital: is there clinical inertia?

BACKGROUND

Effective control of hospital glucose improves outcomes, but little is known about hospital management of diabetes.

OBJECTIVE

Assess hospital-based diabetes care delivery.

DESIGN

Retrospective chart review.

SETTING

Academic teaching hospital.

PATIENTS

Inpatients with a discharge diagnosis of diabetes or hyperglycemia were selected from electronic records. A random sample (5%, n = 90) was selected for chart review.

MEASUREMENTS

We determined the percentage of patients with diabetes or hyperglycemia documented in admission, daily progress, and discharge notes. We determined the proportion of cases with glucose levels documented in daily progress notes and with changes in hyperglycemia therapy recorded. The frequency of hypoglycemic and hyperglycemic events was also determined.

RESULTS

A diabetes diagnosis was recorded at admission in 96% of patients with preexisting disease, but daily progress notes mentioned diabetes in only 62% of cases and 60% of discharge notes; just 20% of discharges indicated a plan for diabetes follow-up. Most patients (86%) had bedside glucose measurements ordered, but progress notes tracked values for only 53%, and only 52% had a documented assessment of glucose severity. Hypoglycemic events were rare (11% of patients had at least one bedside glucose < 70 mg/dL), but hyperglycemia was common (71% of cases had at least one bedside glucose > 200 mg/dL). Despite the frequency of hyperglycemia, only 34% of patients had their therapy changed.

CONCLUSIONS

Practitioners were often aware of diabetes at admission, but the problem was often overlooked during hospitalization. The low rate of documentation and therapeutic change suggests the need for interventions to improve provider awareness and enhance inpatient diabetes care.

Thymic hyperplasia presenting as anterior mediastinal mass in 2 patients with Graves disease

Graves disease is an autoimmune thyroid condition characterized by the production of autoantibodies against the thyrotropin receptor. The autoantibodies mimic the effect of the hormone on thyroid cells, which stimulates autonomous production of thyroxine and triiodothyronine. It has been hypothesized that cross-reactivity of autoantibodies may result in Graves ophthalmopathy and dermopathy. A seldom-recognized feature of Graves disease is thymic hyperplasia. We report 2 patients with Graves disease and incidentally discovered anterior mediastinal masses presumed to be thymic hyperplasia. In both cases, these masses regressed spontaneously after treatment of hyperthyroidism.

Selective estrogen receptor modulators: from bench to bedside and back

OBJECTIVE

To provide a brief review of the history of the development of selective estrogen receptor modulators (SERMs), the current data assessing the effect of SERMs at the organ level, and the mechanism of action of these agents.

METHODS

All the pertinent medical literature was reviewed, and the effects of SERMs on various end-organs were summarized.

RESULTS

SERMs have been available for clinical use since the late 1960s. By the late 1980s, several SERMs had become available that influenced clinical practice. Multiorgan effects of these compounds include variable clinical efficacy for treatment of menopausal symptoms involving the central nervous system, variable effects on the genitourinary tract, and, in general, positive effects on serum lipid levels. SERMs seem to affect bone density positively, albeit to variable degrees, depending on the agent being used. The greatest effect of SERMs has been on the breast, and current SERMs seem to have efficacy for prevention of breast cancer as opposed to the controversial effect of estrogen on the breast. Disadvantages of SERMs include exacerbation of menopausal symptoms and, as with estrogen, an increased incidence of venous thrombosis and pulmonary emboli. SERMs act by modifying the configuration of the estrogen receptor. Effects at the gene transcription level seem to be tissue specific, a factor that likely accounts for the variability of clinical action seen.

CONCLUSION

SERMs are a viable option for treatment of various problems associated with menopause.

Successful pregnancy in a woman with lipoatrophic diabetes mellitus. A case report

BACKGROUND

Lipoatrophic diabetes mellitus is a rare insulin-resistance syndrome. A successful pregnancy occurred in a woman with lipoatrophic diabetes with no antepartum or intrapartum complications except hypertriglyceridemia, treated with gemfibrozil.

CASE

A 29-year-old primigravida had lipoatrophic diabetes most consistent with congenital partial lipodystrophy (Kobberling-Dunnigan syndrome). The antenatal course was remarkable only for a midtrimester rise in serum triglycerides. The patient underwent oxytocin induction and an uncomplicated vaginal delivery.

CONCLUSION

This case demonstrates that women with lipoatrophic diabetes who are otherwise healthy should not be discouraged from trying to conceive. Blood lipids should be checked periodically and hypertriglyceridemia treated to prevent pancreatitis. Gemfibrozil was used in this patient without apparent adverse effects.

When a thyroid abnormality is palpable. What it means and what you should do

Clinicians faced with a palpable thyroid abnormality should ascertain whether there is evidence of thyroid dysfunction, concern for malignancy, and symptoms of obstruction. In the vast majority of cases, laboratory assessment of the thyroid with an sTSH assay establishes the presence or absence of thyroid dysfunction. In a nodular thyroid gland, fine-needle aspiration biopsy is the method of choice for determining whether malignancy is present. In a large goiter, the presence of obstructive symptoms or findings may be a clear indication that surgery is needed. The absence of these findings may warrant simple observation.

Treatment of established postmenopausal osteoporosis with raloxifene: a randomized trial

Raloxifene is a selective estrogen receptor modulator that in experimental animals acts as an estrogen receptor antagonist in breast and endometrium but as an estrogen receptor agonist in the skeletal and cardiovascular systems. We conducted a 1-year prospective, randomized, double-blind trial in 143 postmenopausal osteoporotic women (mean +/- SD age, 68.4+/-5.0 years) with at least one prevalent vertebral fractures and low bone mineral density (BMD), comparing groups receiving raloxifene at 60 mg/day (RLX60) or 120 mg/day (RLX120) and a control group receiving supplements of 750 mg/day of calcium and 400 IU/day of vitamin D. There were no differences among groups in the occurrence of uterine bleeding, thrombophlebitis, breast abnormalities, or increased endometrial thickness (assessed by ultrasonography). As compared with controls, the changes in values over 1 year for RLX60 and RLX120, respectively, were significant for serum bone alkaline phosphatase (-14.9%, -8.87%), serum osteocalcin (-20.7%, -17.0%), and urinary C-telopeptide fragment of type I collagen/creatinine (-24.9%, -30.8%), markers of bone turnover; for serum total cholesterol (-7.0% for RLX60) and low density lipoprotein cholesterol (LDL) (-11.4% for RLX60) and for the LDL/HDL cholesterol ratio (-13.2%, -8.3%). BMD increased significantly in the total hip (1.66% for RLX60) and ultradistal radius (2.92%, 2.50%). There were nonsignificant trends toward increases over controls in BMD for lumbar spine, total body, and total hip (for RLX120). Using a >15% cutoff definition, raloxifene had no effect on incident fractures, but using a >30% cutoff, there was a dose-related reduction (p = 0.047). We conclude that raloxifene therapy is well tolerated, reduces serum lipids, and does not stimulate the uterus or breasts. It has beneficial effects on bone, although, under the conditions of this study, these appear to be of a smaller magnitude than have been reported with estrogen therapy.

Pamidronate: an unrecognized problem in gastrointestinal tolerability

Pamidronate (aminohydroxypropylidine bisphosphonate, APD) is an effective agent for treatment of Paget's disease of bone, and it has also been thought to be effective for treatment of osteoporosis. We desired to study a newer, time-release preparation of pamidronate, and carried out a placebo-controlled, double-masked study of postmenopausal osteoporosis. The original formulation was in a rapidly dissolving gelatin capsule. We encountered four episodes of esophagitis in 49 enrolled patients. We therefore discontinued treatment with this preparation and later began the study again using a standard tablet preparation. We encountered an additional case of erosive esophagitis in 1 patient of 40 receiving this tablet preparation. No patient was receiving concomitant medication which could cause esophagitis. Two of the patients gave a past history of hiatal hernia and 1 gave a history of gastric ulcer 27 years previously. The diagnosis of esophagitis was confirmed in all cases by endoscopy. Healing of the esophagitis promptly ensued after discontinuation of the pamidronate and the use of antacid medication.

Thoracoscopic excision of a peripheral corticotropin-secreting pulmonary carcinoid tumor

Bronchial carcinoid tumors are rare neuroendocrine neoplasms that arise from the Kulchitsky cells of the bronchial epithelium. These tumors can manifest as central carcinoid tumors, pulmonary carcinoid tumorlets, or peripheral carcinoid tumors. Occasionally, the peripheral carcinoid tumors produce corticotropin and result in Cushing's syndrome. Herein we report the first case of Cushing's syndrome associated with a peripheral pulmonary carcinoid tumor that was excised by video-assisted thoracoscopy. After excision, the patient had complete remission. Video-assisted thoracoscopy may be ideal for resecting a peripheral pulmonary carcinoid, especially in patients with debilitation but no evidence of metastasis.

Congenital gigantism due to growth hormone-releasing hormone excess and pituitary hyperplasia with adenomatous transformation

The cause of gigantism in most patients is a GH-secreting pituitary tumor. In this report, a case of congenital gigantism due to probable central hypersection of GH-releasing hormone (GHRH) is described. Normal at birth (4.4 kg; 53 cm), our 7-yr-old male patient grew progressively thereafter to attain a height of 182 cm and a weight of 99.4 kg at the time of our evaluation. The markedly increased baseline plasma levels of GH (730 micrograms/L) did not suppress during a standard 3-h oral glucose tolerance test, but did increase 54% after iv infusion of GHRH. Baseline plasma levels of insulin-like growth factor-I, PRL, and immunoreactive GHRH were also markedly increased. Computed imaging of the head showed a large, partially cystic sellar and suprasellar mass. Extensive imaging studies did not localize a potential source of GHRH. Preoperative treatment with octreotide and bromocriptine for 4 months resulted in a 25% reduction of suprasellar tissue mass. The pituitary tissue removed at transsphenoidal and transfrontal operations showed massive somatotroph, lactotroph, and mammosomatotroph hyperplasia. Areas of GH- and PRL-secreting cell adenomatous transformation were also evident. No histological or immunohistochemical evidence of a pituitary source of GHRH was found. The peripheral plasma immunoreactive GHRH concentration remained unaffected by pharmacological and surgical interventions. We suspect that a congenital hypothalamic regulatory defect may be responsible for the GHRH excess in this case.

Resection of select mediastinal parathyroid adenomas through an anterior mediastinotomy

Two patients who had undergone thorough surgical exploration of the neck were found to have adenomas of fifth parathyroid glands within the mediastinum. After localization with computed tomographic scanning or thallium-technetium imaging, or both, these tumors were resected through a parasternal approach (anterior mediastinotomy); thus, median sternotomy was obviated. This approach has not been described previously for the removal of mediastinal parathyroid tumors.

Case report 653: Arthritis of the wrist due to Mycobacterium avium-intracellulare

We present a case of arthritis of the wrist in an elderly man due to Mycobacterium avium-intracellulare. Prior steroid injections and a surgical procedure on the affected wrist were predisposing risk factors for subsequent mycobacterial involvement of the skeleton. Radiographs demonstrated findings characteristic of tuberculous arthritis: particularly, osteopenia with marginal erosions and diffuse lytic lesions involving the carpals, proximal metacarpals, and distal ends of the radius and ulna. MR scans showed soft-tissue involvement and extensive marrow replacement consistent with infection. It is to be reemphasized that the clinical and radiological findings in this case are very often indistinguishable from TB. The diagnosis depends on the results of tissue culture. Since radiologists are likely to be involved increasingly in interpreting images of immunocompromised patients afflicted with a variety of both typical and atypical infections, it is important occasionally to report rare infections such as that described herein.

Diagnosis of corticotropin-producing bronchial carcinoid tumors causing Cushing's syndrome

Cushing's syndrome due to ectopic production of adrenocorticotropic hormone (corticotropin) has been recognized for many years. Traditionally, clinicians have thought that most cases were due to lung carcinomas and that the clinical manifestations differed from those for pituitary-dependent Cushing's syndrome. We report two cases of corticotropin-producing bronchial carcinoid tumors that were clinically and biochemically indistinguishable from pituitary-dependent Cushing's syndrome. Review of the literature revealed that bronchial carcinoid tumors are the most common cause of Cushing's syndrome due to ectopic secretion of corticotropin. On biochemical and anatomic studies, they are frequently indistinguishable from pituitary-dependent Cushing's syndrome and thus may be difficult to diagnose. Inferior petrosal sinus sampling for corticotropin and computerized imaging of the chest may be the best aids in making the diagnosis.

Insulinoma in a patient with annular pancreas

Intraoperative ultrasonography has facilitated the localization of insulinomas. In this report, we describe a patient who was found to have an insulinoma in association with an annular pancreas. Because such tumors can be in close approximation to major pancreatic ductal structures, intraoperative ultrasonography can be useful for not only localizing the lesion but also delineating the related anatomic features. Although the optimal management of an asymptomatic annular pancreas has not been determined, our patient had no evidence of chronic pancreatitis and no narrowing of the duodenal lumen; therefore, no bowel bypass procedure was done.

The pituitary gland in the Laurence-Moon syndrome

The apparent hypogonadism in patients with the Laurence-Moon syndrome has been variably attributed to unresponsiveness of target organs to gonadal hormones, primary end-organ failure, hypothalamic dysfunction, or pituitary failure. We report the first immunocytologic study of the pituitary gland in this rare disorder. No morphologic abnormalities were noted. The numbers and immunoreactivities of adenohypophyseal cell types were normal. No microscopic abnormalities were evident in the hypothalamus and target organs. The results of our study are consistent with recent biochemical data that suggest that pituitary function is normal in patients with this syndrome.

The hypothalamus and pituitary in cerebral gigantism. A clinicopathologic and immunocytochemical study

Cerebral gigantism, or Sotos' disease, is a rare disorder of unknown cause characterized by the early onset of excessive growth, acromegalic features, and some degree of mental retardation. Although several endocrinologic abnormalities have been described in such patients, none has been specific or sufficient to explain the clinical features. Our report of the endocrinologic and pathologic aspects in a young woman with Sotos' disease includes the first microanatomic study of the hypothalamus and immunocytochemical examination of the pituitary gland in this disorder.

Prolactin cell carcinoma of the pituitary. Clinicopathologic, immunohistochemical, and ultrastructural study of a case with cranial and extracranial metastases

A patient with a primary adenohypophyseal neoplasm who had a long course marked by multiple surgical resections, radiation therapy, and high-dose dopamine agonist therapy developed local invasion as well as cranial and extracranial osseous metastatic lesions. The serum prolactin levels were greatly elevated, and immunohistochemical studies demonstrated prolactin in the cytoplasm of primary and metastatic tumor cells. Ultrastructural features of lactotrophic differentiation, including misplaced granule exocytosis, were observed. This is the third reported case of prolactin cell carcinoma that metastasized despite high-dose dopamine agonist therapy. Analysis of the patient's serum prolactin showed no abnormality in the chromatographic profile of biologic activity.

Gonadotrophin-secreting pituitary tumour: report and review

A 34-year-old male with a pituitary adenoma was investigated and demonstrated to have hypersecretion of both gonadotrophins in the basal state. Immunocytochemical staining and electron microscopic examination were positive for tumour cells secreting FSH and LH. Presenting symptoms included visual disturbances, loss of libido, impotence, cold intolerance, frontal headaches, change in skin pigmentation and excessive weight gain. The patient denied alteration in hair distribution, had no acral features, galactorrhoea or gynaecomastia. Surgical extirpation resulted in complete amelioration of his symptoms over a three year follow-up period. Basal and stimulated pituitary function testing results returned to normal post-operatively. A review of the literature documents six other cases of pituitary tumour secreting both LH and FSH in the basal state. More commonly, the pituitary adenoma secretes FSH only. The literature is reviewed with regard to both types of tumour.

Demonstration of biological activity of prolactin molecular weight variants in human sera

Three immunoreactive forms of PRL, separated by Sephadex G-100 column chromatography, were identified in serum samples from 10 normal subjects and 7 patients with PRL-secreting pituitary tumors. Fractions eluted from the column were assayed for bioactivity by using a sensitive bioassay with the Nb2 cell line. Three molecular weight variants of PRL were identified in normal subjects. In samples from 9 of the 10 normal subjects, 80.1 +/- 3.6% (mean +/- SEM) of the total bioactivity eluted in a peak corresponding to a PRL monomer (peak III) with a mol wt of approximately 24,000, 18.3 +/- 3.7% eluted in a peak with a mol wt of approximately 56,000 (peak II), and 1.6 +/- 1.1% of the biological activity was in the void volume (peak I). In the 10th normal sample, 65% of the total bioactivity was in the void volume (peak I), 31% was in peak III, and 4% was in peak II. Samples from the patients had 3.6 +/- 0.7% of the total bioactivity in peak I, 9.3 +/- 1.0% in peak II, and 87.0 +/- 1.1% in peak III, percentages not significantly different from normal. For comparison with bioassay, RIA measurement of PRL was performed on all fractions of six samples (three normal subjects and three tumor patients). Good correlation was found between RIA and bioassay measurements under each of the three peaks identified. We conclude that 1) in sera from normal subjects, three molecular weight variants of PRL have biological activity; 2) in patients with PRL-secreting tumors, secretion of biologically active PRL molecular weight variants is not proportionately different from that in normal subjects; and 3) the results of the Nb2 PRL bioassay correlate well with PRL levels determined by RIA for each of three molecular weight variants identified.

Idiopathic, sustained, inappropriate secretion of ADH with associated hypertension and thirst

A 15 year old girl presented with excessive thirst and hypertension (170/110 mm Hg). Biochemical investigations revealed serum sodium 118 meq/liter, serum osmolality 238 mosmol/liter, urine sodium 90 meq/liter, urine osmolality 700 mosmol/liter, persistenly elevated serum antidiuretic hormone (ADH) levels (5.8 to 11.9 pg/ml) and no obvious cause for the hypertension. The hypertension is, at least in part, volume-related, diminishing with fluid restriction. Features of gross water intoxication (e.g., confusion, coma) have not occurred. The etiology of the inappropriate secretion of ADH is not obvious but is not thought to be due to "resetting of osmoreceptors" as evidenced by failure to maximally dilute urine following a water load test and persistently elevated serum ADH levels. A similar patient described by Epstein and associates in 1962 is presently well with persistent features of inappropriate secretion of ADH.

U.S. Universities and the World Food Problem

The imponderable now is time. Certainly, it is in short supply if we hope to improve the world's prospects for food production. The requisite scientific skills that can contribute to greater world agricultural production exist in a uniquely concentrated form in the U.S. universities. Incentives for increased university involvement in technical assistance created by the International Development and Food Assistance Act of 1975 will not become effective until a mechanism which guarantees adequate and long-term funding is established. A continuing dialogue to define the nature and scope of needed reforms is necessary if maximum involvement of U.S. scientists in agricultural technical assistance is to be realized. Such involvement is vital in meeting the food needs of the developing world.