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Biomedical subjects

H B Niell

Publications and source records attributed to H B Niell.

At least 19 recordsLinked to original sources
PubMed2005

A randomized phase II trial comparing every 3-weeks carboplatin/paclitaxel with every 3-weeks carboplatin and weekly paclitaxel in advanced non-small cell lung cancer.

BACKGROUND: The optimal schedule of taxane administration has been an area of active interest in several recent clinical trials. METHODS: To address a pure schedule question, we randomized 161 patients with advanced stage IIIB or IV non-small-cell lung cancer (NSCLC) to either paclitaxel 225 mg/m2 every 3 weeks x 4 cycles or 75 mg/m2/week x 12 (cumulative dose on each arm = 900 mg/m2). Both arms received concurrent carboplatin AUC 6 every 3 weeks x 4 cycles. RESULTS: The two arms were well-balanced in terms of known prognostic factors. The overall response rate and survival outcomes were similar on the two arms. There was significantly more grade 3/4 thrombocytopenia and grade 2-4 anemia on the weekly arm but less severe myalgias/arthralgias and alopecia. No difference in the rates of peripheral neuropathy was observed; however, patients on the every 3 weeks arm reported significantly more taxane therapy-related side-effects on the functional assessment of cancer therapy taxane subscale. CONCLUSIONS: This randomized trial exploring schedule-related issues with carboplatin/paclitaxel confirms the versatility of this regimen.

Adult↗
PubMed2001

Extensive stage small cell lung cancer.

Small cell lung cancer is a rapidly proliferating, biologically aggressive form of lung cancer that has a short survival without treatment. Chemotherapy is the foundation of the therapeutic approach to patients with small cell lung cancer. Most patients present with extensive disease, and, although few patients are cured, significant improvement in survival is possible with modern chemotherapy. The role of radiation therapy in extensive disease is palliative, and surgery has little role in patient management. The standard chemotherapy regimen for patients with small cell lung cancer has become either cisplatin or carboplatin with etoposide. Second-line chemotherapy regimens are moderately effective in patients previously responding to initial chemotherapy. Newer chemotherapy agents show promise, but few randomized trials have been completed in extensive disease. Physicians should be encouraged to include their patients with extensive small cell lung cancer in the evolving clinical trials.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Carboplatin/etoposide/paclitaxel in the treatment of patients with extensive small-cell lung cancer.

The purpose of this study was to examine the safety and efficacy of carboplatin/etoposide/paclitaxel in patients with untreated stage IV non-small-cell lung cancer (NSCLC) and extensive small-cell lung cancer (SCLC). Carboplatin was administered intravenously (i.v.) at an area under the curve (AUC) of 6 with etoposide at either 80 or 100 mg/m2 i.v. days 1-3 and paclitaxel at 175 or 200 mg/m2 i.v. over 3 hours along with 5 g/kg of granulocyte colony-stimulating factor subcutaneously on days 4-18, repeated every 3 weeks for 6 courses. Thirty-one patients (five NSCLC and 26 SCLC) entered into this phase I study. The median age was 63 (range, 42 to 74 years), with 24 males and seven females. The recommended dose level for phase II testing was carboplatin AUC = 6, etoposide 80 mg/m2 days 1-3, and paclitaxel 175 mg/m2 over 3 hours. With seven patients at this level, 14% had grade 4 neutropenia, 14% had grade 4 thrombocytopenia, none had grade 2/3 neurotoxicity, and no toxic deaths occurred. One of five (20%) patients with NSCLC responded, and 19 of 22 (86%) evaluable SCLC patients experienced a response to therapy. SCLC patients had a median survival of 10 months. The combination of carboplatin/etoposide/paclitaxel has significant activity with acceptable toxicity in patients with extensive SCLC.

Journal Article↗
PubMed1999

Efficacy of targeted chemoradiation and planned selective neck dissection to control bulky nodal disease in advanced head and neck cancer.

PURPOSE: To determine the efficacy of targeted chemoradiation with the radiation plus platinum (RADPLAT) protocol and planned selective neck dissection in patients with N2 to N3 nodal disease associated with upper aerodigestive tract carcinoma. METHODS: Analysis of 52 patients with N2a, N2b, or N3 disease involving 60 heminecks treated with intraarterial cisplatin, 150 mg/m2, and intravenous sodium thiosulfate, 9 g/m2, on days 1, 8, 15, and 22; radiation therapy, 180 to 200 cGy per fraction for 35 fractions (total dose, 68-74 Gy); and planned neck dissection (33 of 35 procedures were selective). RESULTS: Of the 56 evaluable heminecks, a clinical complete response was achieved in 33 (59%). Within this group, 16 neck dissections were performed, none of which yielded disease on pathological examination. A clinical partial response was obtained in 21 heminecks, of which 18 subsequently had a neck dissection, yielding disease on pathological examination in 14. In all cases, it was possible to completely excise all adenopathy with clear margins on pathological examination. The rate of regional disease control among the 56 evaluable heminecks was 91% (51/56) (median follow-up, 36 months). Four failures were associated with uncontrolled disease at other sites, and 1 was an isolated neck recurrence. CONCLUSION: Selective neck dissection appears to be an effective adjunct to targeted chemoradiation in controlling N2 to N3 neck disease.

Adult↗
PubMed1998

Therapeutic drug monitoring of 21-day oral etoposide in patients with advanced non-small cell lung cancer.

The purpose of this study was to prospectively test a pharmacodynamic model for therapeutic drug monitoring of 21-day oral etoposide. In our previous studies, etoposide trough concentrations on this schedule were related to the hematological toxicity, expressed as WBC and neutrophil counts at the nadir. The following pharmacodynamic model estimated the absolute neutrophil count at the nadir (ANCn) based on the etoposide concentration (Ec) and the pretreatment count (ANCp): ANCn=0.32(1 + ANCp x e(-2.47 x Ec)). Patients were treated with 40 mg/m2/day etoposide p.o. x 21 days and 100 mg/m2 cisplatin i.v. on day 1. All patients had non-small cell lung cancer stage IIIB or IV, had a performance status of 0-2, and had a median age of 66 (range, 42-80). Etoposide was measured in the plasma on day 8 by high-performance liquid chromatography, and dosage adjustments were made for the remainder of the course. We targeted for grade 3 neutropenia (ANCn, 500 to 999/microl) and attempted to avoid grade 4 neutropenia (ANCn, <500/microl). Of 25 patients entered, 22 were evaluable for therapeutic drug monitoring in the first course. Three patients developed grade 3 neutropenia, and seven patients developed grade 4 neutropenia. Etoposide concentrations were significantly correlated with ANCn in the first course (r=-0.50, P < 0.02). For those patients whose dosages were not changed, the estimated correlation between predicted and actual ANCn was 0.77 (P < 0.01). No evidence of significant bias of the pharmacodynamic model was detected. The etoposide dosages were increased in 12 patients and were not changed in the remaining patients. The precision of the model was good in patients whose dosages were not changed but poor in patients whose dosages were increased. The actual observed ANCn was compared with the predicted ANCn based on the pharmacodynamic model. The prediction was considered accurate if the predicted and actual ANCn values were within 500/microl of each other. Using this margin, the ANCn was accurately predicted in 10 of 22 patients. Etoposide concentrations >0.3 microg/ml on this schedule were significantly correlated with combined grades 3 and 4 neutropenia (P < 0.0001). In conclusion, the pharmacodynamic model is statistically sound when applied to a population of patients. However, when applied to individual patients for therapeutic drug monitoring, the model lacks precision and accuracy.

Administration, Oral↗
PubMed1997

Efficacy of targeted supradose cisplatin and concomitant radiation therapy for advanced head and neck cancer: the Memphis experience.

PURPOSE/OBJECTIVE: To evaluate the feasibility, response rates, and toxicity of a Phase II study using targeted supradose cisplatin and concurrent radiation therapy in unresectable Stage III-IV head and neck squamous cell carcinoma. METHODS AND MATERIALS: Sixty patients presenting between 6/93-9/94 were enrolled, 44 (73%) of whom had T4 and/or N2-N3 nodal disease. All patients were treated with rapid targeted superselective intraarterial infusions of cisplatin (150 mg/m2 weekly x 4) and simultaneous sodium thiosulfate intravenously (9 g/m2) for systemic neutralization of cisplatin. Concurrent (day 1) daily radiation therapy was delivered to the primary tumor and overt nodal disease to 66-74 Gy while the uninvolved lower neck received 50 Gy, at 2.0 Gy/fraction. RESULTS: Fifty-one (85%) patients completed the full RADPLAT protocol as planned. Fifty-seven of 60 patients were evaluable for response. Histological (n = 50) or clinical (n = 7) assessment of primary site revealed a complete response (CR) in 52 patients, partial response (PR) in 4, and stable disease (SD) in 1. Of the 40 patients presenting with nodal metastases, pathological (n = 31) or clinical (n = 6) assessment revealed a CR in 25, PR in 11, and SD in 1, while 3 were unevaluable. Overall, for both primary site and nodal disease, CR was attained in 44 (75%), PR in 12 (23%), and SD in 1 (2%) of the 57 evaluable patients. Only 2 (4%) of 57 evaluable patients have recurred above the clavicle, 1 in the primary site and 1 in the regional lymph nodes. Twelve patients (23%) have failed in distant sites. Grade III/VI toxicity has included gastrointestinal in 6, hematologic in 6, mucosal in 12, vascular in 4, and neurological in 4 patients. CONCLUSION: Concurrent radiation therapy and targeted supradose cisplatin (i.e., RADPLAT) can be safely delivered with high response rates and excellent loco-regional control in advanced Stage III/IV head and neck squamous cell carcinoma.

Adult↗
PubMed1995

Phase II study of prolonged oral etoposide in combination with intravenous cisplatin in advanced non-small cell lung cancer.

The objectives of the study were to evaluate the combination of cisplatin and prolonged oral etoposide for response rate, survival, and toxicity. The treatment regimen consisted of etoposide (50 mg/m2/day) p.o. for 21 consecutive days and cisplatin (100 mg/m2) i.v. on day 1 every 28 days for up to six courses. Patients with Stage IIIB or IV non-small cell lung cancer who had not received prior chemotherapy and had an ECOG performance status of 0-2 were eligible if they had normal bone marrow, liver and renal functions. Patients were followed weekly for toxicity including complete blood counts. The total number of patients entered in the study was 60, of whom 56 were male and four female, 40 white and 20 African Americans. Median age was 64 years (range, 39-77). Performance status 0, 1, and 2 was present in five, 39, and 16 patients, respectively. Fourteen patients had Stage IIIB and 46 Stage IV disease. A total of 142 treatment courses were administered (median 2, range 1-6). Three patients had a complete response and 19 patients had a partial response for an objective response rate of 37% (95% confidence interval, 31-43%). Median survival was 5 months (range, 1-39+). Neutropenia was the major toxicity with Grade 4 occurring in 25 patients after the first course. The following percent of patients experienced severe or life-threatening hematologic toxicity (Grade 3 and 4 combined) over all courses: leukopenia, 73%; neutropenia, 73%; anemia, 42%; and thrombocytopenia, 37%. Three patients died of neutropenic sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

Free-riding and the prisoner's dilemma: problems in funding economic analyses of phase III cancer clinical trials.

PURPOSE: Both economic and clinical data on new agents are important to policy-makers who approve pharmaceuticals for widespread use. Randomized clinical trials have been used to evaluate both clinical results and total medical costs associated with new agents. With new expensive pharmaceutical agents, early assessments of economic benefit have taken on greater importance to physicians and patients. Who should provide financial support to these integrated economic and clinical analyses in clinical trials? Here we describe issues that hinder funding of economic analyses and propose potential support mechanisms. RESULTS: The Cancer and Leukemia Group B (CALGB), a large, national cooperative group of academic and community hospitals in the United States, designed a non-small-cell lung cancer (NSCLC) treatment trial to compare two widely used supportive care regimens that varied 20-fold in cost. One important objective of this trial was to compare the cost-effectiveness of the two regimens. While funding for the clinical trial was supported by grants from the National Cancer Institute and the pharmaceutical companies involved in the trial, no specific funding agency was willing and/or able to provide financial support for the economic analyses. After 2 years of planning, the clinical trial was retracted when the funding for the economic analyses could not be secured. The prisoner's dilemma, individual reluctance to support a common social good, explains the lack of funding. CONCLUSION: Economic theory predicts difficulties in evaluating cost-effectiveness of new pharmaceuticals and reluctance to support economic analyses of clinical trials. Economic analyses will require new sources of funds that will not take scarce resources from clinical trials groups. Options for funding include a new federal agency, coordinated work by existing agencies, or academic centers for economic analysis.

Carcinoma, Non-Small-Cell Lung↗
PubMed1994

Cytotoxic effects of alpha- and gamma-interferon and tumor necrosis factor in human bladder tumor cell lines.

We investigated the activity of alpha-interferon (alpha-IFN), gamma-interferon (gamma-IFN) and tumor necrosis factor-alpha (TNF-alpha) in a panel of ten human bladder tumor cell lines. All cytokines were tested at concentrations of 100-10,000 U/ml in a clonogenic assay system. We found that alpha-IFN was active against five of the ten lines while gamma-IFN was only active against one line. TNF was active against five of the ten lines. Maximum synergisms were obtained between the alpha-IFN and TNF, occurring in nine of the ten cell lines. We conclude that alpha-IFN and TNF are active as single agents and synergistic when used together in vitro in human bladder tumor cell lines.

Cell Division↗
PubMed1993

Pharmacodynamics of prolonged oral etoposide in patients with advanced non-small-cell lung cancer.

PURPOSE: This study was undertaken to investigate the pharmacodynamic relationship between etoposide drug levels on 21-day oral treatment courses and hematologic toxicities in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Thirty-two patients with stage IIIB or IV NSCLC were treated with oral etoposide 50 mg/m2/d for 21 consecutive days in combination with cisplatin 100 mg/m2 on day 1. Treatment was repeated every 28 days for up to six courses. Patients had not received previous chemotherapy and had a performance status of 0 to 2. Patients were monitored weekly while on treatment for compliance with oral etoposide and toxicity, including complete blood cell counts, and a blood sample before the daily etoposide dose (drug trough levels). Etoposide concentrations were measured in the plasma by high-performance liquid chromatography (HPLC). RESULTS: Three patients achieved a complete response (CR) and 10 patients a partial response for an objective response rate of 41% (95% confidence interval, 24% to 58%). The median survival was 4 months (range, 1 to 23). Neutropenia was dose-limiting, and two patients died of neutropenic sepsis. Pharmacodynamic correlations for drug concentrations and hematologic toxicities were available for 27 patients and a total of 76 treatment courses, and correlations were significant for graded hematologic toxicity and nadir counts of leukocytes, neutrophils, hemoglobin, and platelets. The grade of infection (77 courses) was also related to drug levels. Using data from 27 initial courses, a pharmacodynamic model was developed to estimate the nadir leukocyte or neutrophil count (WBCn, ANCn) based on the pretreatment count (WBCp, ANCp) and the etoposide concentration (Ec) as follows: WBCn = 0.35 (1 + WBCp x e-1.12 x Ec) and ANCn = 0.32 (1 + ANCp x e-2.47 x Ec). CONCLUSION: Etoposide concentrations are related to the resulting hematologic toxicities. It is possible to predict nadir counts in the first course by a pharmacodynamic model. The above equations need to be validated prospectively and may be useful in future studies of prolonged oral etoposide.

Administration, Oral↗
PubMed1992

Pharmacodynamics of three daily infusions of etoposide in patients with extensive-stage small-cell lung cancer.

The objectives of this study were to define the pharmacodynamics of etoposide and to develop potentially useful models (1) to estimate the plasma clearance using a limited number of samples and (2) to describe the relationship between clearance and the dose-limiting toxicity. A total of 17 patients with extensive-stage small-cell lung cancer were treated with 150 mg/m2 etoposide daily for 3 consecutive days and with 100 mg/m2 cisplatin on day 3 only. Both drugs were given intravenously over 1 h. Treatment was repeated every 21 days for up to six courses. All patients were newly diagnosed (no previous chemotherapy or irradiation) and had a performance status of 0-2. Six patients achieved a complete response as confirmed by repeat bronchoscopy and five patients showed a partial response, for an overall objective response rate of 65% (95% confidence interval, 38%-87%). The median survival was 8 months (range, 1-24+ months). The dose-limiting toxicity was neutropenia. Etoposide pharmacokinetics were measured during the first course and determinations were repeated during courses 3 or 4 and 6. Complete blood counts were obtained weekly. Correlations for etoposide clearance and hematologic toxicities were evaluated for 17 initial courses and for an overall number of 33 courses. Pharmacodynamic correlations were significant for graded hematologic toxicities, as well as nadirs of leukocytes, neutrophils, and platelets for the initial courses and for all courses. To reduce the requirement for numerous blood samples, a limited sampling model was developed to estimate the area under the concentration versus time curve (AUC) with the following equation: AUC = 15.45 + 3.86 x C2 + 7.10 x C4, where C2 and C4 represent the etoposide concentrations at 2 and 4 h, respectively. The total plasma clearance was calculated as the dose divided by the AUC; correlations with toxicity were better for clearance expressed in milliliters per minute than for that expressed in milliliters per minute per square meter of body surface area. The absolute neutrophil count at the nadir (ANCn) can be estimated by the following pharmacodynamic model, which is based on 33 courses: ANCn = -0.399 + 0.024 x Ecl, where Ecl represents the etoposide clearance expressed in milliliters per minute. Further studies are necessary to validate both models prospectively.

Adult↗
PubMed1990

Clonal growth requirements of human bladder tumor cell lines.

We have serially investigated the role of nutrients and growth factors for their ability to support the clonal growth of human bladder tumor cell lines. Five established human bladder tumor cell lines were selected for study of their requirements for clonogenic growth in semisolid cultures. We identified an "optimal medium" to be Alpha MEM medium, 15% horse serum, five micrograms/ml. of transferrin, five micrograms/ml. of insulin and 30 ng./ml. of epidermal growth factor. The "optimal assay" enhanced the growth of human bladder tumor cell lines 2.5 times compared to the standard clonogenic assay. The resulting medium is less complicated to maintain, less expensive and supports the growth of human bladder tumor cell lines better than the standard clonogenic assay.

Cell Line↗
PubMed1989

Combination versus sequential single-agent chemotherapy in the treatment of patients with advanced non-small cell lung cancer.

We have carried out a randomized phase III study in 105 patients with advanced non-small cell lung cancer, comparing a four-drug cisplatin-mitomycin-based combination chemotherapy regimen to sequential single-agent therapy. The combination chemotherapy regimen consisted of mitomycin C (10 mg/m2), vinblastine (5 mg/m2), methotrexate (40 mg/m2), and cisplatin (40 mg/m2) given every 28 days. Sequential single-agent chemotherapy consisted of mitomycin C (10 mg/m2) monthly until progression followed by vinblastine (5 mg/m2) every 2 weeks until progression followed by methotrexate (40 mg/m2) weekly until relapse. Patients failing either regimen were followed with supportive care. The objective response rate for the sequential single-agent therapy was 19% versus 25% for the combination chemotherapy group (P greater than .5). The median survival for the single-agent group was 166 days and 191 days for the combination chemotherapy group. Overall survival was not statistically different between the two groups (P greater than .5). Leucopenia, anemia, and prolonged anorexia with nausea and vomiting were more common in the combination chemotherapy group compared to the single-agent group. This study failed to demonstrate a sufficient therapeutic benefit in the face of the added toxicity for the combination chemotherapy regimen compared to sequential single-agent therapy.

Antineoplastic Agents↗
PubMed1989

5-Fluorouracil infusion and mitomycin combination chemotherapy in the management of patients with advanced non-small-cell lung cancer.

We have carried out a phase II study evaluating the activity of a 5-fluorouracil drug combination in patients with advanced non-small-cell lung cancer. Patients were given 60 mg/m2 of methotrexate i.v. on day 1. On day 2, 750 mg/m2 of 5-fluorouracil was administered as a 24-h infusion daily for 3 days. Also on day 3, 10 mg/m2 of mitomycin was given i.v. along with folinic acid. Folinic acid was started on day 3 initially at a dose of 25 mg/m2 intravenously every 6 h for three doses, followed by a 2-h infusion of 200 mg/m2 daily on days 3 and 4. Therapy was repeated every 28 days. Fourteen of 35 patients (40%) experienced a partial response to chemotherapy. The median survival of the entire group was 19 weeks. Mucositis was a common side effect but severe leukopenia, anemia, renal insufficiency, and skin ulceration were rare. This study demonstrated that 5-fluorouracil infusion therapy has activity in advanced non-small-cell lung cancer but the responses are not durable. Further studies evaluating differing dose schedules and alternate 5-fluorouracil infusion-based drug combinations seems warranted.

Adult↗
PubMed1987

Detection of small cell lung cancer bone marrow involvement by discontinuous gradient sedimentation.

Marrow involvement by small cell lung cancer (SCLC) is detected in 10-23% of patients at initial diagnosis by marrow aspirate and biopsy techniques. To improve the detection and potentially monitor marrow involvement by SCLC we have attempted to concentrate malignant cells with clonogenic potential on a discontinuous density gradient (DDG). The bone marrow from 43 patients with SCLC (36 with histologically negative marrow aspirates and biopsies) were separated on a Ficoll-based DDG. Samples were also separated by conventional Ficoll-diatrizoate (FD) (density, 1.077) gradient sedimentation. The cellular interphase from three fractions (F X) corresponding to specific densities 1.050 (F X 1), 1.055 (F X 2), and 1.060 (F X 3) as well as cells separated by Ficoll-diatrizoate (F X FD) centrifugation were isolated and 2.5 X 10(5) cells from each fraction were cultured in 2 ml of 0.3% agar in McCoy's media with 10% fetal calf serum, 2.5 micrograms transferrin, 1 microgram insulin, and 1% penicillin-streptomycin. Colony growth was assessed after 14 days of culture at 37 degrees C and 6% CO2. Tumor colony growth was seen in eight of 36 (22%) patients with histologically negative marrows as well as in four of seven (57%) patients with known involvement. Mean colony growth per 2.5 X 10(5) cells for all 12 patients was 4.3 colonies for F X 1; 8.8 for F X 2; and 2.7 for F X 3. In contrast mean growth from the F X FD was 1.0 colonies. Cells with clonogenic potential could be demonstrated from F X 2 and F X 3 in seven of 12 and eight of 12 patients, respectively; in F X FD four of 12 patients had tumor growth. We conclude that separation of marrow samples by DDG concentrates malignant cells with clonogenic potential at least 8-fold compared to FD separation and that the sensitivity of the clonogenic assay in detecting marrow involvement by SCLC is enhanced by DDG sedimentation.

Biopsy↗
PubMed1987

Effects of N-trifluoroacetyladriamycin-14-valerate (AD-32) on human bladder tumor cell lines.

We have compared the in vitro activity of N-trifluoroacetyladriamycin-14-valerate (AD-32) and doxorubicin hydrochloride (ADR) on the clonal growth of human bladder tumor cell lines (HBTCL). In order to determine the relatively toxicity of ADR and AD-32 on hematopoietic stem cells, CFU-GM assays were set up using 10 normal human bone marrow samples. The mean lethal dose for 50% of the colonies (LD-50) for ADR was 1.6 +/- 1.4 microM and that for AD-32, 3.9 +/- 4.9 microM (P less than 0.55), suggesting that these agents have similar bone marrow toxicity. Both drugs produced enhanced inhibition of clonal growth of HBTCL with increasing C X Ts. The spectrum of activity of the two drugs was similar against a panel of seven HBTCL. The activity of ADR was inhibited at 4 degrees C while the activity of AD-32 was unaffected by temperature. ADR was more effective against HBTCL in the log growth phase than the plateau phase while the reverse was found using AD-32. Verapamil was found to enhance the activity of both ADR and AD-32 against a HBTCL (T24), found to be resistant to both agents. The lipophilic properties of AD-32, along with its enhanced activity when used over prolonged periods of time and its activity against tumor cells in the plateau phase, suggest that AD-32 could be useful in the management of patients with superficial bladder cancer.

Biological Transport↗
PubMed1987

Evidence for depressed humoral immunity to Pneumocystis carinii in homosexual males, commercial plasma donors, and patients with acquired immunodeficiency syndrome.

Heterosexual controls were found to have significantly higher titers of immunoglobulin G antibody to Pneumocystis carinii than did patients with the acquired immunodeficiency syndrome (AIDS) and P. carinii pneumonitis, human immunodeficiency virus (HIV) antibody-positive or -negative homosexual male "gay bar" patrons, and HIV antibody-positive or -negative commercial plasma donors. The T-helper/T-suppressor lymphocyte ratios of HIV antibody-negative homosexual male gay bar patrons were slightly depressed (mean = 1.31 +/- 0.54) compared with those of heterosexual controls (mean = 1.79 +/- 0.32). In addition to other recognized factors, preexisting humoral as well as cell-mediated immune deficits before infection with HIV may help to explain the prevalence of and morbidity and mortality associated with P. carinii pneumonitis in AIDS patients.

Acquired Immunodeficiency Syndrome↗