Pharmacokinetic evaluation of the combination of zidovudine and didanosine in children with human immunodeficiency virus infection

As part of a phase I/II trial in children infected with human immunodeficiency virus, we studied the pharmacokinetics of zidovudine and didanosine administered as single agents and in combination. Zidovudine (60 to 180 mg/m2 per dose) was given orally every 6 hours, and didanosine (60 to 180 mg/m2 per dose) every 12 hours. Pharmacokinetic samples were obtained from 54 patients and the area under the plasma concentration-time curve (AUC) was estimated by means of a previously defined limited sampling strategy. Follow-up blood samples were obtained after 4 and 12 weeks of treatment. The mean AUC for zidovudine ranged from 4.8 mumol.hr per liter at 60 mg/m2 to 11.0 mumol.hr per liter at the 180 mg/m2 level, and increased in proportion to the dose. The mean AUC for didanosine ranged from 2.8 mumol.hr per liter (60 mg/m2) to 8.0 mumol.hr per liter (180 mg/m2), with a wide interpatient variability. The AUCs of zidovudine and didanosine remained unchanged when the agents were administered in combination. There was no significant change in the AUCs of either drug after 4 and 12 weeks in comparison with those on day 3 of therapy. However, there was greater interpatient and intrapatient variability with didanosine than with zidovudine. These observations have implications for the future utility of therapeutic drug monitoring with these agents.

Elevated levels of tumor necrosis factor-alpha in Zairian neonate plasmas: implications for perinatal infection with the human immunodeficiency virus

Plasma levels of tumor necrosis factor-alpha (TNF alpha) and the ability of plasmas to induce HIV expression in chronically infected cell lines were measured in samples from adults, cord blood, and neonates from Zaire and North America. Plasma levels of TNF alpha were higher in Zairian neonates born to HIV-negative and -positive mothers than in uninfected Zairian adults (612 vs. 128 vs. 8 pg/mL, P < .001); this dichotomy persisted until children were 9 months old. Plasmas from neonates of HIV-negative Zairian mothers also stimulated higher levels of reverse transcriptase from HIV-infected cell lines than did plasma from HIV-negative Zairian adults (1339 vs. 110 cpm, P < .001). Similar patterns were noted in plasmas from HIV-negative North American adults and neonates; however, TNF alpha levels were markedly lower, and smaller differences were noted among North American adults and neonates than those in the Zairian cohort. Markedly elevated plasma TNF alpha levels in Zairian neonates and infants may play a role in the pathogenesis and progression of HIV disease in this patient population.

Development of papillary renal cell tumours is associated with loss of Y-chromosome-specific DNA sequences

Twenty-two papillary renal cell tumours were analysed by Southern hybridization using eight DNA probes from homologous regions of the X and Y chromosomes and two Y-chromosome-specific DNA probes. Sixteen of the 19 papillary renal cell tumours of male patients showed the loss of Y-chromosome-specific sequences. No loss of heterozygosity was detected in three tumours that developed in females. The frequency of loss of the Y chromosome was established in 50 non-papillary renal cell carcinomas as well. Only seven of the 31 non-papillary renal cell carcinomas obtained from male patients had lost the Y-chromosome-specific sequences, whereas no allelic loss was found in 19 non-papillary tumours obtained from female patients. Papillary renal cell tumours show a strong male preponderance (6:1) and loss of Y chromosome in 84 per cent of the cases, whereas non-papillary renal cell carcinomas show only a slight male preponderance (1.5:1) and the Y chromosome is lost in only 22 per cent of the cases. These data suggest that a tumour suppressor gene is localized at one of the homologous regions of the X and Y chromosomes, the homozygous inactivation of which is associated with the development of papillary renal cell tumours.

Zidovudine and didanosine combination therapy in children with human immunodeficiency virus infection

OBJECTIVE

Zidovudine and didanosine are both beneficial for the treatment of human immunodeficiency virus (HIV) infection in children. Because disease progression and toxicity often limit their long-term use as single agents, new approaches to using nucleoside analogues are necessary to improve current antiretroviral therapy.

DESIGN

We conducted a phase I-II study to evaluate the tolerance, pharmacokinetics, and antiviral activity of the combination of zidovudine and didanosine in children with HIV infection. Sixty-eight children who were either previously untreated or who had manifested hematologic toxicity on full-dose zidovudine were enrolled. Eight dose combinations were studied in the previously untreated children, with doses of zidovudine ranging from 90 to 180 mg/m2 every 6 hours and doses of didanosine ranging from 90 to 180 mg/m2 every 12 hours.

RESULTS

Fifty-four previously untreated HIV-infected children were enrolled in this part of the study, of whom 49 remained in the study for a minimum of 24 weeks. For children with previous zidovudine-related hematologic toxicity, three dose levels with zidovudine at 60 mg/m2 every 6 hours orally and didanosine ranging from 90 to 180 mg/m2 every 12 hours orally were used. A total of 14 children were enrolled in this part of the study, and 12 remained on therapy for at least 24 weeks. No evidence of new or enhanced toxicity was observed in either group. After 24 weeks, the median CD4 cell count for all patients increased from 331 to 556 cells/mm3 (P = .01). For the previously untreated group, the median increase in CD4 counts was from 386 to 726 cells/mm3 (P = .003). The median p24 antigen concentration (in those with a detectable level at baseline) decreased from 95 to < 31 pg/mL (p < .001). The geometric mean titer of HIV in plasma decreased from 83.1 to 2.7 tissue culture infectious doses/mL (P = .001).

CONCLUSIONS

The combination of zidovudine and didanosine was well-tolerated at doses as high as those used in single agent therapy. Potent in vivo antiviral activity was observed. Combination therapy with nucleoside analogues may be an important approach to optimizing the use of these agents in the treatment of HIV infection.

XX sex reversal in a llama

A 5-month-old llama was examined for evaluation of sexually ambiguous external genitalia. To determine the phenotypic, chromosomal, and gonadal sex of the llama, transrectal palpation and ultrasonography, contrast cystography, karyotype evaluation, laparoscopy, and necropsy were performed. A karyotype of 74,XX and finding of components of the müllerian duct system were suggestive of a female phenotype and chromosomal sex. On histologic evaluation, however, components of the wolffian duct system also were found, and the gonads were composed entirely of testicular tissue. The diagnosis was XX sex reversal, with a XX male phenotype.

The radial forearm flap in intraoral reconstruction after a pull-through operation

Free fasciocutaneous forearm flaps, based on the radial artery, were used to replace the tissue defect caused by pull-through operations for cancer of the floor of the mouth in 11 patients. There was no total or partial flap failure. The greatest advantage of the method is that restriction of the tongue movement is less when compared with the results of other methods. The thin forearm flaps are adaptable and pliable. The newly developed lower alveolar crest and the sublingual sulcus make prosthetic rehabilitation possible.

Diagnosis of Pneumocystis carinii pneumonia by multiple lobe, site-directed bronchoalveolar lavage with immunofluorescent monoclonal antibody staining in human immunodeficiency virus-infected patients receiving aerosolized pentamidine chemoprophylaxis

The yields of both induced sputum examination and bronchoalveolar lavage (BAL) have been reported to be decreased for breakthrough episodes of Pneumocystis carinii pneumonia in human immunodeficiency virus-infected patients receiving aerosolized pentamidine chemoprophylaxis. This study assessed whether the yield of a single middle or lower lobe BAL could be increased by the utilization of two techniques: (1) indirect immunofluorescent staining with a combination of two murine monoclonal anti-Pneumocystis antibodies in addition to routine toluidine blue O and cytopathologic staining, and (2) the performance of multiple lobe, site-directed BAL (i.e., both upper lobe and middle or lower lobe lavage, including the lobe with the greatest radiographic abnormality). Results of 252 fiberoptic bronchoscopies performed at the National Institutes of Health and the Los Angeles County-University of Southern California Medical Center were analyzed. P. carinii pneumonia was documented in 21 episodes in patients who did not receive prior anti-Pneumocystis chemoprophylaxis and in 41 episodes in patients who received aerosolized pentamidine. Monoclonal antibody staining and multiple lobe, site-directed BAL resulted in similar diagnostic yields for P. carinii in the nonprophylaxis (100%) and aerosolized pentamidine (98%) groups. If BAL had been performed without monoclonal antibody staining and multiple lobe, site-directed lavage, then the yield would have decreased to 95% in the nonprophylaxis group and to 80% in the aerosolized pentamidine group.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitochondrial and chromosomal DNA alterations in human chromophobe renal cell carcinomas

Renal cell tumours are characterized by the loss of chromosome 3p and trisomy of 5q segments (common, non-papillary renal cell carcinoma), or by trisomy of chromosomes 7 and 17 and loss of the Y chromosome (papillary renal cell carcinoma), or by random karyotype changes and mitochondrial DNA alterations (renal oncocytoma). We have studied by means of RFLP analysis the genomic and mitochondrial DNA in 11 chromophobe renal cell carcinomas, which have a unique morphology among kidney cancers. We found a loss of the constitutional heterozygosity at chromosomal regions 3p, 5q, 17p, and 17q, a combination of allelic losses that has not been found in other types of renal cell tumours. Three of the tumours showed a gross alteration in the restriction pattern of the mitochondrial DNA. A combined morphological and genetic analysis suggests that chromophobe renal cell carcinoma is a distinct entity.

Low chromosome number in chromophobe renal cell carcinomas

Cytogenetic analysis revealed low chromosome number, telomeric association, and pulverisation of chromosomes in three chromophobe renal cell carcinomas. One fully karyotyped and a previously published case showed the common loss of chromosomes 1, 2, 6, 10, 13, 17, and 21.

CD4 T-lymphocyte counts and Pneumocystis carinii pneumonia in pediatric HIV infection

The relationship between CD4 T-lymphocyte counts and infection with the human immunodeficiency virus (HIV) is retrospectively investigated for 266 HIV-infected and uninfected children who were born to infected women, including 39 with Pneumocystis carinii pneumonia (PCP), in a population-based surveillance study. Of 21 perinatally HIV-infected children with PCP only 10 (48%) had CD4 T-lymphocyte counts that were less than 500 x 10(6) cells/L (500 cells/mm3), compared with all 18 who were infected via blood transfusions or clotting factors. Among 68 children who were 1 year or younger, 18 (90%) of 20 PCP cases had CD4 T-lymphocyte counts that were less than 1500 x 10(6) cells/L (1500 cells/mm3) compared with only five (10%) of 48 children who did not have the acquired immunodeficiency syndrome (odds ratio, 77.4; 95% confidence interval, 19.7 to 313.4). The mean CD4 T-lymphocyte count was lower for the 39 PCP cases when compared with the 188 children who were at different stages of HIV infection and did not have the acquired immunodeficiency syndrome (AIDS) independent of age. The majority of perinatally HIV-infected children with PCP were 6 months or younger and 50% were previously unknown to be infected. Thus, HIV-positive children should be identified early and followed closely. CD4 T-lymphocyte counts may be useful in monitoring HIV-positive children and determining when to begin PCP prophylaxis.

Cystic medial necrosis of the aorta in patients without Marfan's syndrome: surgical outcome and long-term follow-up

A retrospective analysis was performed to determine the surgical outcome and long-term follow-up of patients with documented cystic medial necrosis of the aorta. Ninety-three patients were diagnosed as having cystic medial necrosis at the Cleveland Clinic between July 1963 and December 1987 (72% men aged 26 to 77 years, mean 55). Patients who met the standard diagnostic criteria for Marfan's syndrome were deliberately excluded. Sixty-eight percent of the patients had a diastolic murmur and chest roentgenogram revealed a dilated aortic arch in 58% and cardiomegaly in 63%. Cardiac catheterization in 76 patients demonstrated aortic root dilation in 78%, aortic regurgitation in 72%, aortic dissection in 32% and coronary artery disease in 32%. Ninety patients underwent surgery including composite graft repair with reimplantation of the coronary arteries in 34%. Follow-up, obtained on 90 (97%) of the 93 patients, ranged in duration from 0 to 137 months (mean 29). Thirty-four of the 90 patients died (age range 30 to 75 years, mean 60). Ninety-four percent of the known causes of death were related to the cardiovascular system; 65% were the result of aortic dissection or rupture or sudden death. Ninety-six percent of survivors were in New York Heart Association functional class I or II. Overall estimated survival at 1, 3 and 5 years was 72.2%, 63.5% and 57.4%, respectively. Actuarial survival in patients who underwent composite graft reconstruction was 84% at 5 years. The presence of a diastolic murmur at initial presentation was associated with a poor prognosis (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Ebstein's anomaly: natural and unnatural history

Clinical features and natural history were analyzed in 30 patients with Ebstein's anomaly (mean age 26 years, range 1.5-58 years, 53% females). The main presenting symptoms were dyspnea and fatigue (83%). At presentation, there were six patients (20%) in New York Heart Association Functional Class (NYHAFC) I, nine (30%) in NYHA-FC II, and 15 (50%) in NYHA-FC III or IV; 12 patients (40%) were cyanotic. Common auscultatory findings were widely split second heart sound in 21 (70%), third heart sound in 14 (47%), fourth heart sound in 16 (53%), and a systolic murmur in 22 (73%). Right bundle branch block was present in 21 (70%), documented supraventricular tachycardia in seven (23%), and Wolff-Parkinson-White syndrome in three (10%). Catheterization was performed in 93% without complications. Fourteen patients were treated surgically (12 [86%] in NYHA-FC III or IV, 10 [71%] with associated anomalies); tricuspid valve replacement was performed in eight, atrial septal defect repair in two, accessory pathway ablation in two, right atrial plication in one, and automatic cardioverter defibrillator implantation in one. Surgical treatment improved 10 patients from NYHA-FC III or IV to NYHA-FC I or II. Death occurred in nine patients (five treated surgically and four medically); four of these deaths were sudden. In the eight patients who had tricuspid valve replacement, there were one operative and two late deaths. The authors conclude that surgical therapy with tricuspid valve replacement improves the clinical status of patients who are severely ill. Risk of sudden death remains an important problem in patients with Ebstein's anomaly regardless of severity of the disease and mode of treatment.

Marfan's syndrome: natural history and long-term follow-up of cardiovascular involvement

A retrospective analysis was undertaken to define the natural history and long-term follow-up of a group of patients with Marfan's syndrome. Eighty-four patients were diagnosed between January 1959 and June 1987 as having Marfan's syndrome; 68% were male; their ages ranged from 2 to 67 years (mean 26.6). Sixteen patients constituted the early surgical group (those who underwent surgery before 1979; mean age 36.1 years). Nineteen patients constituted the late surgical group (surgery in 1979 or later; mean age 33.3 years). The nonsurgical group comprised 49 patients (mean age 19.3 years). Fifty-seven percent of the patients had a diastolic murmur and 38% had cardiomegaly at presentation. Fifty-seven percent underwent cardiac catheterization, which revealed aortic root dilation (85%), aortic regurgitation (73%), aortic dissection (33%) and mitral regurgitation (36%). Thirteen of the 19 patients in the late surgical group received a composite graft repair of the ascending aorta as compared with only 2 of the 16 in the early surgical group. Follow-up information was obtained on 81 (96%) of 84 patients; the follow-up time was 2 to 332 months (mean 99). Thirty-one of the 81 patients died at age 3 to 63 years (mean age 35 years); 87% of the known causes of death were related to the cardiovascular system. Sixty-one percent of deaths were the result of aortic dissection or rupture or sudden cardiac death. Of the 50 survivors, 98%, including all patients in the late surgical group, were in functional class I or II. Overall survival at 5, 10 and 15 years after operation was 78.4%, 57.1% and 49.5%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)