Efficacy of 810 nm diode laser in hair reduction in Indian subpopulation using a novel Gabor filter-based detection software and hair algorithm

BACKGROUND

Diode laser (810 nm) is frequently employed for hair reduction. There are few studies determining the efficacy in Indian population.

OBJECTIVES

Assessment of efficacy and safety of 810 nm diode laser in facial/axillary hair reduction and objective assessment of the improvement with dermoscopy, photographs, and novel Gabor filter-based hair detection algorithm.

METHODOLOGY

This hospital-based study included 40 adult women with 108 treatment sites over 5.4 sessions (range 4-8). Evaluation of treatment areas (hair texture, density) was done using modified Ferriman-Galwey scoring. Photography and dermoscopic images were taken before each session and 6 weeks after the last. Immediate and delayed adverse reactions were noted. Assessment of efficacy was done by patient, principal, and blinded investigator using Global Aesthetic Improvement scale (GAIS) and hair detection algorithm (evaluating characteristics of dermoscopic hair).

RESULTS

The fluences ranged from 16 to 29 Joules/cm² with pulse width of 30 ms. Upper lip (n = 29, 26.9%) and chin (n = 25, 22.1%) were commonly treated areas. Improvement in hair texture and density (reduction in uniformly distributed, terminal hair from 37.1% to 13.9%) was statistically significant (p < 0.0001). Excellent improvement of 75-100% (GAIS) was noted by principal and blinded investigator in 24.1% and 33.3% total sites, respectively. The median improvement, calculated by the algorithm, was 60% for side locks, 53.9% for axilla, 24.1% for upper lip, and 14.9% for chin. Axilla and upper lip were sites associated with maximum discomfort. Epidermolysis and paradoxical hypertrichosis were seen in five patients each.

CONCLUSION

The 810 nm diode laser is safe and effective in the reduction of dark, coarse terminal hairs in Fitzpatrick skin types III-V. Inter-observer variation and investigator bias in the assessment of efficacy can be successfully overcome by using the algorithm.

Guidelines for bath PUVA, bathing suit PUVA and soak PUVA

BACKGROUND

The aim of these guidelines is to encourage dermatologists to use bath psoralen plus ultraviolet A (PUVA), bathing suit PUVA and soak PUVA in the treatment of psoriasis vulgaris and other conditions.

METHODS

Evidence was collected using searches of the PubMed, MEDLINE and COCHRANE databases using the keywords "bath PUVA," "soak PUVA," "bathing suit PUVA" and "turban PUVA." Only publications in English were reviewed.

RESULTS

One hundred and thirty-eight studies were evaluated, 57 of which fulfilled the criteria for inclusion.

CONCLUSIONS

Both bath PUVA and bathing suit PUVA are very effective and safe treatments for generalized stable plaque psoriasis (strength of recommendation, A). Soak PUVA is very effective in the treatment of both palmoplantar psoriasis and chronic palmoplantar eczema (strength of recommendation, A).

Anything Rare is Possible: Letrozole Induced Eczematous Skin Eruption

Letrozole is used as first line drug in postmenopausal women with early-stage or advanced hormone-sensitive breast cancer. Letrozole has favourable tolerability profile when administered once daily and significant adverse reactions occur rarely. The objective of this report is to describe a case of eczematous skin eruption that occurred during letrozole treatment. A 61-year-old female patient was admitted with lump in the left breast. FNAC, HPE were done and the patient was diagnosed to have invasive ductal breast carcinoma. After a month of completing CT and EBRT, the patient was given 2.5 mg OD tab. letrozole at night. She developed itchy skin lesions over the right thigh that later generalised, at 6- weeks of treatment. The lesion has been defined as eczematous moderate to severe drug eruption. These lesions were attributed to letrozole therapy and recurred within 24h after rechallenge. Drug eruption is associated with many drugs but this is the first such report with letrozole. We suggest of being aware of such reactions during letrozole usage.

Efficacy and safety of erbium-doped yttrium aluminium garnet fractional resurfacing laser for treatment of facial acne scars

BACKGROUND

Treatment of acne scars with ablative fractional laser resurfacing has given good improvement. But, data on Indian skin are limited. A study comparing qualitative, quantitative, and subjective assessments is also lacking.

AIM

Our aim was to assess the improvement of facial acne scars with Erbium-doped Yttrium Aluminium Garnet (Er:YAG) 2940 nm fractional laser resurfacing and its adverse effects in 25 patients at a tertiary care teaching hospital.

METHODS

All 25 patients received four treatment sessions with Er:YAG fractional laser at 1-month interval. The laser parameters were kept constant for each of the four sittings in all patients. Qualitative and quantitative assessments were done using Goodman and Barron grading. Subjective assessment in percentage of improvement was also documented 1 month after each session. Photographs were taken before each treatment session and 1 month after the final session. Two unbiased dermatologists performed independent clinical assessments by comparing the photographs. The kappa statistics was used to monitor the agreement between the dermatologists and patients.

RESULTS

Most patients (96%) showed atleast fair improvement. Rolling and superficial box scars showed higher significant improvement when compared with ice pick and deep box scars. Patient's satisfaction of improvement was higher when compared to physician's observations. No serious adverse effects were noted with exacerbation of acne lesions forming the majority.

CONCLUSION

Ablative fractional photothermolysis is both effective and safe treatment for atrophic acne scars in Indian skin.Precise evaluation of acne scar treatment can be done by taking consistent digital photographs.

A simple instrument designed to provide consistent digital facial images in dermatology

Photography has proven to be a valuable tool in the field of dermatology. The major reason for poor photographs is the inability to produce comparable images in the subsequent follow ups. Combining digital photography with image processing software analysis brings consistency in tracking serial images. Digital photographs were taken with the aid of an instrument which we designed in our workshop to ensure that photographs were taken with identical patient positioning, camera angles and distance. It is of paramount importance in aesthetic dermatology to appreciate even subtle changes after each treatment session which can be achieved by taking consistent digital images.

Erythema elevatum diutinum associated with scleritis

Erythema elevatum diutinum (EED) is a chronic and rare variant of leukocytoclastic vasculitis that is being reported nowadays frequently in association with HIV infection. It clinically manifests as asymptomatic to tender erythematous papules, plaques and nodules, usually with acral distribution and is rarely accompanied by systemic complaints other than arthralgia. The reported associations include preceding upper respiratory infections, hematological malignancies, lymphomas and monoclonal gammopathies. Here we report a 45 year old man with multiple joint pains, tender nodules over palms and soles and ocular pain and congestion, who was subsequently diagnosed as a case of EED and scleritis following histopathological examination. Skin as well as ocular complaints completely subsided with Dapsone monotherapy.

Development of sulforaphane-encapsulated microspheres for cancer epigenetic therapy

Even though conventional chemotherapeutic management of cancer has reduced morbidity and mortality to a great extent, virtually all chemotherapeutic agents cause damage to healthy cells, necessitating exploration of novel anticancer agents that exert their effects through an alternate mode of action. Objectives of our research were twofold. First, we explored the promising potential of histone deacetylase inhibitor sulforaphane for epigenetic therapy for cancer as this therapeutic approach aims to reverse aberrant epigenetic modifications that affect gene expression. In vitro cell culture studies performed using B16 and S91 melanoma cells showed that sulforaphane inhibited growth and proliferation of cancer cells by downregulating deacetylation enzymes. The second part of our research investigated polymeric drug delivery systems to increase therapeutic efficacy and to minimize potential side effects of R,S-sulforaphane. Albumin microspheres encapsulating sulforaphane were developed by spray drying. Microspheres were characterized for their morphology, size and zeta potential. Cell culture studies using melanoma cells and in vivo studies in melanoma tumor-bearing C57BL/6 mice demonstrated that albumin based polymeric delivery system was efficacious and has the potential to enhance the therapeutic effect and anticancer activity of sulforaphane.

Erythema nodosum leprosum as the presenting feature in multibacillary leprosy

Leprosy is an ancient disease that has survived into the modern ages despite an intense effort to eliminate it worldwide. Here we report a case of a 32-year-old woman who had recurrent painful nodules of six months duration. Because of a lack of lesions suggestive of leprosy, she was initially diagnosed to have cutaneous vasculitis and erythema nodosum. However, because of the persistent nature of her condition she was later detected to have leprosy and erythema nodosum leprosum (ENL) with the aid of simple diagnostic tests.

Analysis of in vitro and in vivo sensitivity of oral cancer cells to methotrexate

AIM

The present study was directed on the assessment of the response of treatment-naive oral cancer cells to methotrexate (MTX) in vitro: and clinical response to MTX therapy.

METHODS

A pilot study of in vitro: evaluation of MTX response of oral cancer cells from 10 patients was conducted using a cell viability assay to determine the sensitivity/resistance to MTX. Quantitative in vitro: data were correlated to the clinical outcome to MTX therapy.

RESULTS

A positive correlation was observed between the effect of MTX on tumor cells in vitro: and clinical response for 7 out of 10 patients.

CONCLUSIONS

Observations from the proof-of-principle pilot study suggests that oral cancer cells have intrinsically variable response to MTX. Confirmation of these findings with a larger cohort of patients could aid in the development of individualized therapies for this class of malignancy.

Epithelioid sarcoma: a diagnostic challenge

Epithelioid sarcoma is an uncommon slow-growing soft tissue malignancy, associated with a high incidence of local recurrence and metastasis. We report a 26-year-old male with epithelioid sarcoma on the right palm with a long history of over seven years, which was initially misdiagnosed as cutaneous tuberculosis and epithelioid hemangioendothelioma, as a result of which the treatment was delayed. No metastasis was found in our patient. The patient was referred to the oncology centre where he underwent wide excision of the lesion followed by radiotherapy. The review of the literature including clinical and histological differential diagnosis is presented as it mimics inflammatory, benign tumors as well as other malignant conditions.

Expression of oncofoetal marker carcinoembryonic antigen in oral cancers in South India--a pilot study

Expression of the oncofoetal glycoprotein, carcinoembryonic antigen (CEA), has been observed in a number of malignancies and is also being pursued as a target for anti-cancer therapy. This study explored the status of this biochemical entity in the oral squamous cell carcinoma (SCC) in South India caused by extensive chewing habits. Squamous cell carcinoma in the study belonged to grade I and grade II. Tumour staging of the patients recruited in the study ranged from T2N1M0 to T4N3M0. Of the grade II cases studied, 88% (7 out of 8) showed expression of CEA. The 2 cases of grade I SCC of buccal mucosa also showed positive anti-CEA staining. If the results from this pilot study can be validated with a larger sample size, a role can be attributed to this tumour marker in oral neoplasia, thereby opening up avenues for using CEA as an additional diagnostic marker in oral SCC in this population and as a possible target for anti-cancer therapy.

Microsurgical anatomy of the middle cerebral artery

BACKGROUND

The microsurgical anatomy of the middle cerebral artery (MCA) is of particular interest to the cerebrovascular surgeon. The purpose of this study was to define the microsurgical anatomy of the MCA and its various branches in the Indian population.

METHODS

Ten MCAs were studied from five cadaveric brain specimens. The authors studied the outer diameter, length, branches, perforators and site of these on the main trunk (M1), the division of the main trunk, the secondary trunks and their various cortical branches using the operating microscope under 5-20x magnification.

RESULTS

The outer diameter of the MCA main trunk ranges from 2.5 to 4 mm with a mean of 3.35 mm. The superolateral branches consisted of polar temporal artery and anterior temporal artery that had a common origin and sometimes the uncal artery or the accessory uncal artery. Perforators or lenticulostriate arteries were seen in the inferomedial surface all along the length of M1. Eight bifurcations and two trifurcations were noted. Cortical branches and their origin are discussed.

CONCLUSION

Although the microsurgical anatomy of the MCA in Indian population correlated with the findings in the western literature, some structural and statistical variations were noted.

Treatment modalities for hepatitis B viral infection and resistance to antiviral therapy

The worldwide problem of hepatitis B viral infection has been the focus of a large number of investigations. In the last decade advances have been made in the understanding of the viral function as well as strategies to combat the virus. Lamivudine, Hepsera, and interferon-alpha therapies that are currently used in the clinic are not optimal because of the emergence of resistance in the former modality and/or adverse effects. There are several new nucleosides that are under development for treatment of HBV. With the combination of a number of treatment protocols, it should be possible to bring down the viral load to undetectable levels and minimize the risk of generating mutations that confer resistance to the therapeutic agent.

Non-bullous variant of bullous pemphigoid: role of immunofluorescence in diagnosis

An elderly lady presented with persistent and unexplained excoriated lesions on trunk and limbs of 4 years' duration. No vesicles or bullae ever developed during the course of the disease. Histopathology showed nonspecific dermatitis. The diagnosis of bullous pemphigoid was confirmed by immunofluorescence. The patient responded well to topical steroids and dapsone.

YSDD: a novel mutation in HBV DNA polymerase confers clinical resistance to lamivudine

The emergence of drug-resistant virus in hepatitis B virus (HBV) patients treated with lamivudine is well documented. In this study, we determined the mutations occurring in the tyrosine-methionine-aspartate-aspartate (YMDD) amino acid motif of the HBV DNA polymerase gene, as well as upstream and downstream of this region, in patients with breakthrough virus during lamivudine therapy. Thirty-one Turkish patients (20 patients HBeAg positive, 11 patients HBeAg negative and anti-HBe positive) with chronic HBV infection who completed at least 104 weeks of lamivudine treatment were investigated. All patients received lamivudine, (150 mg/day), for 104 weeks, with or without 4 months of interferon (IFN) combination. HBV-specific sequences were amplified by polymerase chain reaction (PCR) from sera of patients with breakthrough virus, and the PCR products were directly analysed by sequencing. Breakthrough virus was detected in seven of the 31 patients (22.6%) between 9 and 18 months of therapy. Of the seven patients, six were HBeAg positive at baseline, and four had a double mutation consisting of rtM204V and rtL180M, while two had an rtM204I change. In one patient, two base substitutions at rt204 (ATG --> AGT; T to G and G to T) lead to a methionine to serine change (YMDD --> YSDD). This novel DNA pol mutation was detected at month 18 of lamivudine treatment. In addition, this new variant had the rtL180M mutation and a 12 base pair deletion in the pre-S1 region between nucleotides 43-54. The YSDD mutation was still present 6 months after lamivudine discontinuation. In vitro transfection studies also confirmed that the YSDD strain is resistant to lamivudine. In conclusion, the results indicate that, in addition to a Met --> Val and Met --> Ile change in YMDD, a Met --> Ser change at rt204 (YMDD --> YSDD) associated with the rtL180M change can also emerge during lamivudine treatment, which confers lamivudine resistance in vivo and in vitro, leading to virological breakthrough and ALT increases.

Foramen magnum metastatic malignant melanoma

The foramen magnum as a site for brain metastasis is extremely rare. We report the case of a 24-year-old male who presented with features of increased intracranial pressure and lower cranial nerve palsies. Imaging revealed a foramen magnum tumor with extension up to the cerebellar vermis superiorly and into the spinal canal inferiorly (craniospinal mass) with mild obstructive hydrocephalus. A malignant melanoma was completely excised. The patient continued to be tumor-free 24 months later.

Secondary holocord syringomyelia with spinal hemangioblastoma: a report of two cases

Intramedullary spinal hemangioblastoma is well known to be accompanied by syringomyelia. However, holocord secondary syringomyelia is uncommon. We present 2 cases of spinal hemangioblastoma, one in the conus medullaris and the other in midthoracic region, accompanied by holocord syrinx. In both the cases the secondary syrinx resolved following successful total tumor excision with good neurological recovery.

A fatal case of erythema necroticans

Erythema nodosum leprosum (ENL) classically presents as tender, erythematous nodules over the face, arms and legs. Severe ENL can become vesicular or bullous and break-down and is termed erythema necroticans (Jopling & McDougall, 1996) and is treated with corticosteroids. The causes of death in a majority of leprosy patients are the same as in the general population, with the exception of renal damage in lepromatous leprosy. There is possible increased mortality from side-effects of antileprosy drugs, steroids, or other drugs used in reactions, from toxaemia in severe reactions, and from asphyxia due to glottic oedema (Jopling & McDougall, 1996). We report here a case of erythema necroticans, the cause of death being septicaemia, secondary to skin ulcers and urinary tract infection, precipitated by corticosteroids.

Quantitative estimation and recommendations for supplementation of protein lost through scaling in exfoliative dermatitis

BACKGROUND

Exfoliative dermatitis (ED) can result in protein loss due to scaling causing a negative nitrogen balance. Freedberg and Baden (J Invest Dermatol 1962; 38: 277-284) estimated the amount of scale lost in ED by collecting it in an occlusive suit. Subsequently, the nitrogen content was determined by the Kjeldahl method. The exact amount of protein supplementation in ED, dependent on scale loss, is not well established. As occlusion and hyperthermia caused by the suit can inhibit scaling, the objectives of the present study were to design an alternative method to measure the amount of scale lost, to estimate the protein content of the scale, and to propose suitable recommendations for protein supplementation.

METHODS

In 40 patients with ED, the total protein content lost through scaling per day (P) was determined by the following equation: P = TxIxYxX/25x10(4) g, where T is the total body surface area in square meters, I is the percentage area involved in scaling, estimated using computer-aided design (CAD graph), Y is the amount of scale lost per unit area (0.0025 m2) in milligrams, and X is the quantity of protein present in 1 g of scale in milligrams estimated by a spectrophotometer.

RESULTS

It was observed that patients with ED secondary to drug reactions, eczema, and psoriasis lost 7.2, 9.6, and 22.6 g of scale with a protein content of 4.2, 5.6, and 12.8 g respectively. The difference in the amount of protein lost in ED secondary to drug reactions and eczema was not statistically significant; however, the protein lost in psoriasis was significant (p < 0.01 to p < 0.05).

CONCLUSIONS

ED may increase the daily protein loss by approximately 25-30% in psoriasis and 10-15% in other causes. Standard treatment for ED and protein supplementation based on our recommendations can minimize the adverse effects of a negative nitrogen balance.

Telomerase from human leukemia cells: properties and its interaction with deoxynucleoside analogues

Telomerase is a unique reverse transcriptase involved in the maintenance of genomic integrity. In an attempt to understand the properties of this enzyme and to study the effect of deoxynucleoside analogues, we have isolated and partially purified telomerase from the blast cells of a patient with acute myelogenous leukemia. During the course of purification of telomerase, three characteristic forms of this enzyme activity were separated. Two processive forms and one less processive form were noted. All forms of the enzyme activities could be abolished by RNase A and proteinase K treatments, implying that they are ribonucleoproteins. The major form of telomerase was characterized with respect to divalent ion requirements, effect of salt and nonionic detergents. The Km of deoxynucleoside triphosphates was determined with a modified telomerase repeat array protocol assay. Studies with deoxynucleoside analogues indicated that 3'-azido-3'deoxythymidine triphosphate is much more inhibitory than 2',3'-dideoxy 2',3'didehydrothymidine triphosphate, and the cytidine analogue ddCTP was not inhibitory. ddGTP was the most potent inhibitor among all dideoxynucleosides studied.

Inhibition of replication of hepatitis B virus by cytallene in vitro

The acyclic cytosine nucleoside analog cytallene [1-(4'-hydroxy-1',2'-butadienyl)cytosine], which has both (+)- and (-)-enantiomers, was evaluated for its anti-hepatitis B virus (HBV) activity in 2.2.15 cells and was found to have potent activity against HBV DNA synthesis. The R-(-)-enantiomer was found to be the more active of the cytallene enantiomers, with a 50% inhibition concentration against HBV synthesis (HBIC50) of 0.08 microM. Its antiviral activity could be reversed by deoxycytidine (dC) and less efficiently by cytidine. Upon removal of the R-(-)-enantiomer from culture medium, the synthesis of HBV DNA could reinitiate, which suggested that the antiviral action is reversible. The R-(-)-enantiomer was also found to be more cytotoxic than the S-(+)-enantiomer. The degree of cytotoxicity varied among the cell lines, with a 50% inhibition of cell growth at greater than 10 microM. The R-(-)-enantiomer had no effect on HBV RNA synthesis and mitochondrial DNA synthesis at a concentration of 10 times or more than the HBIC50. The two enantiomers cannot be deaminated by dC deaminase, and they can be phosphorylated by cytoplasmic dC kinase. The R-(-)-enantiomer of cytallene is the first acyclic cytosine analog with potent inhibitory activity against HBV similar to those of other L-(-)-ddC analogs.

Ventral screw fixation of odontoid fracture, using single fluoroscope

This paper is a detailed description of an improvised operative technique used by us, for ventral screw fixation in a case of type II odontoid fracture.

Structure--activity relationships of 1-(2-Deoxy-2-fluoro-beta-L-arabinofuranosyl)pyrimidine nucleosides as anti-hepatitis B virus agents

Since 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil (L-FMAU) has been shown to be a potent anti-HBV agent in vitro, it was of interest to study the structure-activity relationships of related nucleosides. Thus, a series of 1-(2-deoxy-2-fluoro-beta-L-arabinofuranosyl)pyrimidine nucleosides have been synthesized and evaluated for antiviral activity against HBV in 2.2.15 cells. For this study, L-ribose was initially used as the starting material. Due to the commercial cost of L-ribose, we have developed an efficient procedure for the preparation of L-ribose derivative 6. Starting from L-xylose, 6 was obtained in an excellent total yield (70%) through the pyridinium dichromate oxidation of the 3-OH group followed by stereoselective reduction with NaBH4. It was further converted to the 1,3,5-tri-O-benzoyl-2-deoxy-2-fluoro-alpha-L-arabinofuranose (10), which was then condensed with various 5-substituted pyrimidine bases to give the nucleosides. Among the compounds synthesized, the lead compound, L-FMAU (13), exhibited the most potent anti-HBV activity (EC50 0.1 microM). None of the other uracil derivatives showed significant anti-HBV activity up to 10 microM. Among the cytosine analogues, the cytosine (27) and 5-iodocytosine (35) derivatives showed moderately potent anti-HBV activity (EC50 1.4 and 5 microM, respectively). The cytotoxicity of these nucleoside analogues has also been assessed in 2.2.15 cells as well as CEM cells. None of these compounds displayed any toxicity up to 200 microM in 2.2.15 cells. Thus, compound 13 (L-FMAU), 27, and 35 showed a selectivity of over 2000, 140, and 40, respectively.

Structure-activity relationships of cytotoxic cholesterol-modified DNA duplexes

Short DNA duplexes with cholesterol linked at the 3'-terminus of each strand have unique, selective cytotoxic properties. The structural requirements for biological activity were explored through chemical synthesis of analogs and testing in cultured hepatoma cells. Effects of modifications to the sequence, backbone, 3'-sterol, 3'-linker, and 5'-terminus were evaluated. Self-complementary 3'-modified oligodeoxynucleotide (ODN) 10-mers were prepared from solid supports bearing the modification and linker of interest. Any changes to the normal phosphodiester backbone were poorly tolerated. The presence of cholesterol or a closely related sterol was an absolute requirement for activity. The length and position of attachment of the linker to cholesterol was important, with longer linkers showing reduced activity. Large, lipophilic groups at the 5'-terminus gave reduced cytotoxicity and poor solubility properties. The short length and unique structure of these ODNs allowed efficient automated synthesis on a 400 mumol scale and simplified purification.

Use of 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil as a novel antiviral agent for hepatitis B virus and Epstein-Barr virus

A novel anti-hepatitis B virus (anti-HBV) agent, 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil (L-FMAU), was synthesized and found to be a potent anti-HBV and anti-Epstein-Barr virus agent. Its in vitro potency was evaluated in 2.2.15 and H1 cells for anti-HBV and anti-Epstein-Barr virus activities, respectively. In vitro cytotoxicity in MT2, CEM, 2.2.15, and H1 cells was also assessed, and the results indicated high antiviral selectivities of L-FMAU in these cells.

Synthesis and biological evaluation of 2',3'-dideoxy-L-pyrimidine nucleosides as potential antiviral agents against human immunodeficiency virus (HIV) and hepatitis B virus (HBV)

Various 2',3'-dideoxy-L-cytidine,2',3'-dideoxy-L-uridine, and 3'-deoxy-L-thymidine analogues have been synthesized and evaluated in vitro as potential anti-HIV and anti-HBV agents. Coupling of 1-O-acetyl-5-O-(tert-butyldimethylsilyl)-2,3-dideoxy-L-ribofuranose (1) with silylated derivatives of 5-fluorocytosine, cytosine, 5-fluorouracil, uracil, and thymine in the presence of ethylaluminum dichloride gave the corresponding nucleosides 2, 3, 4, 5, 10, 11, 12, 16, 17, and 18 as a mixture of alpha- and beta-anomers, which were then deblocked to yield the corresponding 2',3'-dideoxy-L-5-fluorocytidine derivatives, 6 and 7, 2',3'-dideoxy-L-cytidine derivatives, 8 and 9, 2',3'-dideoxy-beta-L-fluorouridine (13), 2',3'-dideoxy-beta-L-uridine (14), and 3'-deoxy-L-thymidine derivatives, 15 and 19. Among these 2',3'-dideoxy-L-nucleoside analogues, 2',3'-dideoxy-beta-L-5-fluorocytidine (6, beta-L-FddC) was found to be the most active against HIV-1, which is approximately 3 and 4 times more active against HIV-1 in vitro than 2',3'-dideoxy-beta-D-cytidine (ddC) and 2',3'-dideoxy-beta-D-5-fluorocytidine (beta-D-FddC) with ED50 values of 0.5, 1.5, and 2 microM, respectively. The dose-limiting toxicity of ddC is severe neuropathy which may be caused by the inhibition of the synthesis of mitochondrial DNA. ddC has an IC50 value of 0.022 microM against host mitochondrial DNA synthesis. Conversely, the IC50 values for beta-L-FddC and beta-L-ddC are > 100 microM; therefore, neuropathy may not present itself to be a problem with beta-L-FddC and beta-L-ddC as chemotherapeutic agents. In addition, beta-L-FddC and 2',3'-dideoxy-beta-L-cytidine (8, beta-L-ddC) demonstrated equally potent activity against HBV in vitro by having the same ED50 value of 0.01 microM. Both beta-L-FddC and beta-L-ddC, which have an "unnatural" L-configuration in the sugar moiety, are approximately 1000 and 280 times more potent, respectively, against HBV than the D-configuration beta-D-FddC and ddC which have an ED50 values of 10 and 2.8 microM. In view of the potent antiviral activity of beta-L-FddC against both HIV-1 and HBV and potent antiviral activity of beta-L-ddC against HBV in vitro, their low cytotoxicity, and especially the negligible inhibitory effect on host mitochondrial DNA synthesis, beta-L-FddC and beta-L-ddC merit further development as potential anti-HIV and anti-HBV agents.

Antiviral activity of 2',3'-dideoxy-beta-L-5-fluorocytidine (beta-L-FddC) and 2',3'-dideoxy-beta-L-cytidine (beta-L-ddC) against hepatitis B virus and human immunodeficiency virus type 1 in vitro

2',3'-Dideoxy-beta-L-5-fluorocytidine (beta-L-FddC) and 2',3'-dideoxy-beta-L-cytidine (beta-L-ddC), two nucleosides with "unnatural L-configuration," have been synthesized and found to have potent antiviral activity against hepatitis B virus (HBV) and human immunodeficiency virus type 1 (HIV-1) in vitro with very little toxicity. At 1 microM, both beta-L-ddC and beta-L-FddC inhibited the growth of HBV by more than 90%, while at the same concentration the D-configuration counterparts, 2',3'-dideoxy-beta-D-cytidine (ddC) and 2',3'-dideoxy-beta-D-5-fluorocytidine (beta-D-FddC), did not show antiviral activity against HBV. The order of anti-HIV-1 activity was beta-L-FddC > ddC; beta-D-FddC > beta-L-ddC. The dose-limiting toxicity of ddC is neuropathy which is believed to be caused by the inhibition of the synthesis of mitochondrial DNA. ddC severely inhibited the mitochondrial DNA synthesis of CEM cells yielding an IC50 value of 0.022 microM. Conversely, both beta-L-FddC and beta-L-ddC did not demonstrate any inhibition against mitochondrial DNA synthesis up to 100 microM concentration.

The origin of the cancer cell: oncogeny reverses phylogeny

The formulation in 1874 of the biogenetic law by Ernst Haeckel as "ontogeny recapitulates phylogeny" emphasized the structural similarities detected in metazoans between their developmental and ancestral forms. More recently, many workers have independently commented on the similarities observed between the behaviours displayed by dedifferentiated cancer cells and their embryonic precursors. This review will explore a possible linkage between these disparate observations and will suggest that cancer cells behave in ways that are reminiscent of primitive eukaryotic cells. In particular, we suggest that the acquisition of a multicellular level of organization during early metazoan evolution required a critical and difficult change in growth strategy as germ line and somatic cells became distinct. Whereas unicellular free living eukaryotes follow a simple strategy of rapid division as long as conditions permit, the elaboration of powerful growth inhibitory pathways must have been necessary in primitive multicellular organisms to enable some but not all sister cells to stop dividing, even under conditions of nutrient abundance. This limitation on cellular growth would than have permitted the appearance of tissues and organs with differentiated characteristics, ultimately enabling the enhanced survival of the meiotic lineage. Cancer cells might therefore be considered to represent, with their loss of tumor suppressor inhibitory activity and elevation of oncogene stimulatory activity, a reversion to a more primitive evolutionary state capable of indeterminate growth at the expense of the host. By this analogy, the growth phenotypes displayed by cancer cells, embryonic cells, and free-living eukaryotes are fundamentally similar.

Overexpression of c-myc by amplification of negative promoter domain

Amplification of myc proto-oncogenes has been reported in many human malignancies, but whether the amplified genes are properly regulated has not been well studied. Transcription factors that control gene expression are of limited abundance, and we have previously shown (Johnston, R.N., and Kucey, B.L. (1988) Science 242, 1551-1554) that amplified heat shock promoter sequences can compete with natural heat shock genes for these factors, resulting in heat shock gene disregulation. To establish whether protooncogenes may also be disregulated in this manner, a previously identified negative regulatory domain from the human c-myc promoter was amplified by up to 800-fold in Chinese hamster ovary cells. The amplified cells showed up to a 14-fold increase in hamster c-myc transcript abundance when compared with controls and also displayed reduced doubling times, enhanced incorporation of tritiated thymidine, elevated growth in soft agar, and a fusiform morphology, consistent with an elevation in the degree of cellular transformation. We infer that overexpression of endogenous hamster c-myc genes in the experimental cells was elicited in trans by sequestration of an inhibitory factor or complex that bound to excess nonfunctional human c-myc promoter domains. The transcriptional inhibitory activity we detect is consistent with anti-oncogene function.

Metabolism of fensulfothion by a soil bacterium, Pseudomonas alcaligenes C1

Fensulfothion (O,O-diethyl O-[4-(methylsulfinyl)phenyl]phosphorothioate), an organophosphorus pesticide used to control the golden nematode Heterodera rostochiensis, is used as a source of carbon by microorganisms isolated from soils treated with the pesticide. Two of the microbial isolates, Pseudomonas alcaligenes C1 and Alcaligenes sp. strain NC3, used more than 80% of the pesticide in 120 h in culture when supplemented as a source of carbon. P. alcaligenes C1, which showed maximal growth on fensulfothion, degraded the compound to p-methylsulfinyl phenol and diethyl phosphorothioic acid. The phenolic metabolite could be identified by conventional spectral analysis, whereas the spectral patterns of the phosphorus-containing metabolite suggested that the compound was complexed with some cellular molecules. However, utilization of the phosphoric acid ester and ethanol by P. alcaligenes C1 suggested that the microbe attacks fensulfothion by an initial hydrolysis of the compound and subsequent utilization of the phosphoric acid ester. The pathway of degradation of fensulfothion by P. alcaligenes is of great value in the detoxification of the pesticide residues and also in the environmentally stable phosphoric acid esters.

Tumor promotion studies in rat tracheal epithelium

The tracheal epithelium of the Fischer 344 rat is histologically very similar to that of the human bronchus. Also, carcinomas of tracheal origin in F-344 rats are similar in morphology to human bronchogenic carcinomas. Tumor promotion in rat tracheal epithelium was studied by using two model systems. The first is a heterotopic transplant system in which rat tracheas are implanted subcutaneously on the backs of isogenic recipents. In the first system, the epithelium was topically exposed to pellets containing 7,12-dimethylbenz(a)anthracene (DMBA), used as the initiating agent, followed by pellets containing the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), the promoting agent. After 98 weeks, a three- to fourfold increase in the percentage of tracheas having malignant tumors was seen in tracheal transplants receiving both DMBA and TPA compared to DMBA alone. Exposure of the tracheal grafts to TPA alone resulted in epithelial hyperplasia and inflammation, but no dysplastic lesions. The second system is an organ culture-cell culture system in which small pieces of trachea are grown in organ culture, then epithelial cells are grown from these pieces as primary cell cultures. The organ cultures were exposed to the direct alkylating agent, N-methyl-N'-nitro-N -nitrosoguanidine (MNNG) used as the initiator, then multiple short exposures to TPA were used to promote. Primary cell cultures and cell lines were then established from these explants. After 52 weeks, a five-fold increase in the percentage of explants producing tumorigenic cell lines was observed when MNNG + TPA-exposed explants were compared to MNNG-exposed explants. Tracheal explants exposed to TPA alone produced many cell lines but none tested were tumorigenic. These two systems provide a means to study tumor promotion in respiratory epithelium. The evidence more importantly suggests that airborne promoting substances may play a key role in the development of bronchogenic carcinoma.

Evaluation of mutagenic effect of the fungicide fenaminosulf in Drosophila melanogaster

Fenaminosulf (p-dimethylaminobenzenediazo sodium sulfonate, CAS registry No. 140-56-7) which is an active ingredient in several commercial fungicides was reported to be mutagenic in Salmonella typhimurium (McCann et al., 1975), Bacillus subtilis (Kada et al., 1974) and shown to cause chromosome aberrations in plants (Zutshi and Kaul, 1975). Since fenaminosulf has structural similarity to the potent carcinogen, butter yellow (p-dimethylaminoazobenzene, CAS registry No. 60-11-7), the present studies were undertaken to evaluate the mutagenic potential of this fungicide in Drosophila melanogaster. Fenaminosulf administered at 10 mg/100 ml food medium failed to induce sex-linked recessive mutations in Drosophila. Since Drosophila has drug-metabolizing enzymes similar to those of mammals (Vogel, 1975), it is suggested that the lack of mutagenic activity of fenaminosulf could be due to the conversion of fenaminosulf to non-mutagenic derivatives in Drosophila.

Purification of a bacterial organophosphate-hydrolysing phosphatase by Cibacron 3GA-Sepharose affinity chromatography

A phosphatase catalysing the hydrolysis of organophosphorus pesticides was purified to homogeneity using Cibacron 3GA-Sepharose CL 6B affinity chromatography. The enzyme which is localized in the periplasm of the bacterium Alcaligenes NC5 was extracted by treating with 0.2M MgCl2, pH 8.4. The enzyme was adsorbed to the Cibacron-Sepharose at pH 7.0 and eluted with Tris-HCl buffer at pH 8.0, with 47 per cent recovery. The enzyme thus obtained was electrophoretically homogeneous. This simple affinity purification procedure enhances the potential for its use in large scale detoxification systems.

Neoplastic transformation of primary tracheal epithelial cell cultures

Primary cultures of rat tracheal epithelial cells were treated with the chemical carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) to quantitatively study the early events during neoplastic transformation. Epithelial cells were dissociated from tracheas of specific-pathogen-free Fischer-344 rats and were plated on collagen-coated tissue culture dishes. To determine cytotoxicity, cells were exposed on day 1 to various concentrations of MNNG for 3 h and colony forming efficiency (CFE) was determined on day 7. MNNG at a concentration of 0.1 microgram/ml did not decrease CFE as compared to the control cultures, whereas 1 microgram/ml reduced the CEF by 75%. For transformation studies, primary cell cultures received single exposures to MNNG (0.1-0.6 microgram/ml) or multiple exposures to 0.1 microgram/ml of MNNG for 3 h between days 1 and 17. In carcinogen-exposed cultures, morphologically altered foci appeared on day 18, recognizable by high cell density. Transformation frequencies between 1 and 8% were observed depending on MNNG concentration. Cultures containing altered foci continued to grow during the third and fourth week when control cultures had ceased to proliferate and exfoliated from the dish. Over 40% of the cultures which received multiple exposures to MNNG acquired cell line status and could be subcultured greater than or equal to 20 times. None of the 30 control cultures became cell lines. Seventy per cent of MNNG-exposed cell lines showed the anchorage independent growth phenotype at passage 20 as judged by growth in agarose. Four of 10 cultures exposed either 6 or 8 times to MNNG formed invasive squamous cell carcinomas at passage 20 upon inoculation into nude mice. Based on these and previous studies, we feel that unrestricted cell replication is an early key event in carcinogen-exposed epithelial cell populations, preceding neoplastic transformation.

Identification of early carcinogen-induced changes in nutritional and substrate requirements in cultured tracheal epithelial cells

The purpose of our studies was to determine whether specific differences in nutritional and/or substrate requirements exist between normal and carcinogen treated tracheal epithelial cells. Epithelial cells were collected from control tracheas or from tracheas exposed in vivo for 4 weeks to the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA). This carcinogen exposure was shown in previous studies (18) to induce various types of transformed epithelial cell phenotypes. The cells were cultured under 7 different culture conditions, one of which was designed to provide optimum growth conditions for all cells (nonselective condition = SC0) and contained F12, conditioning factors from 3T3 fibroblasts, Dulbecco's minimal essential medium (DME), insulin, transferrin, hydrocortisone, fetal bovine serum (FBS) and bovine hypothalamus extract. By removing one or more factors from SC0 we hoped to design conditions selecting against normal and for "carcinogen altered" cells. It was found that normal cells require collagen and conditioning factors (CF) (produced from 3T3 fibroblasts grown in DME + 2% FBS) for growth in hormone supplemented medium. Increasing the serum concentration to 10% did not compensate for the collagen and CF requirements. In comparison, cells from carcinogen-exposed tracheas clearly had reduced nutritional and substrate requirements. Such cells grew for at least 30 days without collagen substratum as long as CF were present or without CF as long as collagen was present. High serum concentration replaced the requirement for both collagen and CF. Immortalization and anchorage independence of growth occurred in all cultures derived from DMBA-exposed tracheas except in those maintained in high serum but without DME, collagen and CF. These studies indicate that "carcinogen-altered" cells can be identified and selected for based on substrate and nutrient requirements. This should be useful in designing a quantitative epithelial transformation system.

The exotoxin of Bacillus thuringiensis: a new C-mitotic agent

Thuringiensin A, an exotoxin from Bacillus thuringiensis, a constituent of the microbial insectide thuricide has been found to inhibit mitotic spindle, condense and scatter chromosomes. It may therefore be a promizing tool in future cell biological studies.