A pilot clinical/pharmacological study of the protein kinase C-specific inhibitor safingol alone and in combination with doxorubicin

We performed a pilot clinical trial with safingol (L-threo-dihydrosphingosine), a protein kinase C-specific inhibitor that potentiates the effect of doxorubicin (DOX) in tumor-bearing animals. Safingol was initially administered as a 1-h infusion at escalating doses. Fourteen days later, patients received the same dose of safingol in combination with a fixed dose of DOX. The combination was repeated at 3-week intervals. Safingol dose levels ranged from 15 to 120 mg/m2. The plasma levels achieved at the final dose level were comparable to those associated with potentiation of DOX in animals. The mean Cmax and area under the curve for safingol at the 120 mg/m2 dose level were 1040 +/- 196 ng/ml and 1251 +/- 317 mg x h/ml, respectively. The mean plasma half-life for safingol was 3.97 +/- 2.51 h, the mean estimated clearance was 3140 +/- 765 ml/min, and the mean volume of distribution was of 995 +/- 421 liters. Coadministration of a fixed dose of DOX did not significantly change the pharmacokinetics of safingol, nor did increasing doses of safingol significantly affect the pharmacokinetics of DOX. Minor responses were observed in three patients with pancreatic cancer and one patient with angiosarcoma of the scalp. This pilot Phase I study indicates that the protein kinase C inhibitor safingol can be given safely with 45 mg/m2 of DOX at a dose that is potentially pharmacologically active without dose-limiting toxicity.

Interleukin-4 blocks the release of collagen fragments from bovine nasal cartilage treated with cytokines

Interleukin-1 (IL-1) in combination with other cytokines can induce a reproducible release of collagen fragments from bovine nasal cartilage in culture. Over 70% of the total collagen is released by day 14 and this release is accompanied by the appearance of collagenolytic activity in the medium that cleaves collagen specifically at the one quarter/three quarter position. Interleukin-4 is able to prevent the release of collagen fragments from the tissue and this is accompanied by a reduced secretion and activation of collagenase (MMP-1) with an increase in tissue inhibitor of metalloproteinases-1 (TIMP-1). IL-4, especially in the presence of IL-1, increased TIMP secretion by bovine nasal cartilage in culture. These results suggest that IL-4 is able to specifically block cartilage collagen resorption by down-regulating the production of collagenase (MMP-1) and up-regulating TIMP-1 by chondrocytes within the cartilage.

Physical mapping of the human neurotensin gene (NTS) between markers D12S1444 and D12S81 on chromosome 12q21

Neurotensin (NTS) is an endogenous tridecapeptide of the central nervous system and the gastrointestinal tract of different mammalian species including human. The human gene encoding neurotensin has previously been assigned to chromosome 12 but no regional localization was available. We now confirm this assignment and place the NTS gene on the physical and cytogenetic maps. The NTS gene is located on a yeast artificial chromosome contig that contains several polymorphic markers and is close to a polymorphic marker located at 95.8 cM on the Généthon linkage map. NTS is immediately proximal to four polymorphic markers, including D12S81 (AFM102xg9) and D12S88 (AFM158yb4). Using fluorescence in situ hybridization, we map the gene cytogenetically to band 12q21.

Is vagal innervation to the atrioventricular node impaired after radiofrequency ablation of the slow atrioventricular nodal pathway?

To assess the potentially adverse effects of RF catheter ablation (RFCA) of the slow AV nodal pathway on the parasympathetic innervation to the AV node in patients with AV nodal reentrant tachycardia (AVNRT), AV nodal conduction was evaluated following vagal stimulation by means of a phenylephrine bolus injection (200 micrograms) before and after RFCA in ten patients (mean age, 37 +/- 14 years). Nine patients with AV reentrant tachycardia (AVRT) due to a left free wall accessory pathway served as a control group (mean age of 37 +/- 12 years). Whereas no prolongation of the AH interval was observed in the AVNRT group following the phenylephrine bolus during sinus rhythm, despite a significant slowing in sinus rate, phenylephrine administration in AVRT patients was associated with both slowing of the sinus rate and prolongation of the AH interval. Following successful RFCA, the same responses were observed. To delineate the indirect effect of heart rate on AV conduction in response to the phenylephrine bolus, the AH interval was also measured during fixed atrial pacing. A marked prolongation of the AH interval occurred in both groups following phenylephrine administration. This prolongation was biphasic in 50% of AVNRT patients before ablation, suggesting a predominant effect of vagal stimulation on the fast AV nodal pathway. RFCA was associated with disappearance of discontinuous AV conduction in all but one patient with AVNRT. Vagal stimulation caused the same amount of AH interval prolongation as before RFCA in both study groups. In conclusion, patients with AVNRT have a preserved modulation of AV nodal conduction in response to vagal stimulation during sinus rhythm. In addition, vagal stimulation seems to exert a predominant effect on the fast AV nodal pathway. RFCA of the slow AV nodal pathway in patients with AVNRT does not cause detectable damage to the vagal innervation to the AV node.

Characterization of the cDNA and gene encoding human PDE3B, the cGIP1 isoform of the human cyclic GMP-inhibited cyclic nucleotide phosphodiesterase family

Two distinct PDE3 [cyclic GMP-inhibited cyclic nucleotide phosphodiesterase (cGI PDE)] isoforms, cGIP1 and cGIP2, have been identified. Here we report cloning of the cDNA and gene encoding human (H)cGIP1 (classified as PDE3B). The cDNA encodes a protein of 1112 amino acids (approximately 123 kDa). Northern blots indicate that its mRNA is expressed in several adipose tissue depots. The human PDE3B gene is composed of 16 exons spanning more than 114 kb and was localized to chromosome 11p15 by in situ hybridization. Exon/intron boundaries were determined, and genetic polymorphism, confirmed by single-strand conformational polymorphism of DNA from 25 healthy subjects, was demonstrated in exon 4 at nucleotide 1389 (A/G). Two polymorphic dinucleotide repeat sequences were identified in introns 5 and 12.

Predictors of Alcohol Use Among Rural Adolescents

There is increasing evidence that alcohol use is becoming more common during childhood and early adolescence. However, little is known about alcohol use among rural youths. This article reports a study of alcohol use among 367 fifth-grade students in two rural South Carolina school districts. More than one third (n = 131) of the fifth graders reported having used alcohol. Of these, 34 percent (n = 44) reported drinking during the previous month; 8 percent had been intoxicated during the previous two months; and 54 percent reported drinking in the home with or without parental approval. Logistic regression analysis was used to determine the predictors of alcohol use by fifth graders. The results indicated that gender (OR = 2.82), mother's alcohol use (OR = 1.86), father's alcohol use (OR = 2.13), and smoking (OR = 8.30) were significantly associated with alcohol use. The findings suggest that prevention programs address cigarette smoking and drinking behaviors of parents to reduce alcohol use and the acquisition of other health compromising behavior by youths. Early intervention approaches must go beyond the schools and target families as well as community populations.

Influence of reduced carotid body drive during sustained hypoxia on hypoxic depression of ventilation in humans

To evaluate whether the intact hypoxic drive from the carotid bodies during sustained hypoxia is required for the generation of hypoxic depression of ventilation (VE), 16 volunteers were exposed to two consecutive periods of isocapnic hypoxia (first period 20 min; second period 5 min; end-tidal PO2 45 Torr) separated by 6 min of normoxia. In study A, saline was given. In study B, 3 micrograms.kg-1.min-1 i.v. dopamine (DA), a carotid body inhibitor, was given during the first hypoxic exposure followed by saline during normoxia and the second hypoxic exposure. In study C, 20 min of normoxia with DA preceded 6 min of normoxia and 5 min of hypoxia without DA. The first peak hypoxic VE (PHV) in study A was approximately 100% above normoxic VE. After 20 min of hypoxia, VE declined to 60% above normoxic VE. The second PHV in study A was only 60% of the first PHV. We relate this delayed recovery from hypoxia to "ongoing" effects of hypoxic depression. During DA infusion, the changes in VE due to sustained hypoxia were insignificant (study B). The second PHV in study B was not different from the PHV after air breathing in studies A and C. This indicates that the recovery from sustained hypoxia with a suppressed carotid body drive was complete within 6 min. Our results show that despite central hypoxia the absence of ventilatory changes during 20 min of isocapnic hypoxia due to intravenous DA prevented the generation of central hypoxic depression and the depression of a subsequent hypoxic response.

Costs of HIV+/AIDS at CD4+ counts disease stages based on treatment protocols

We report treatment protocols for HIV+/AIDS patients by CD4+ counts (T-lymphocyte cells/mm3: > or = 500, 499-200, 199-50, and < 50) as a tool to provide better definition and to project annual costs (total charges for services) and lifetimes costs for HIV+/AIDS. The treatment protocols, derived from the literature and an HIV+/AIDS Physician Panel, defined the resource use associated with antiretroviral therapy and opportunistic disease prophylaxis and treatment. Resource use costs were derived from the published literature, insurance database, Medicare fee schedules, surveys, and the Physician Panel. At CD4+ counts, the rates of opportunistic diseases were derived from the Physician Panel experience; the mean occupancy times were derived from the literature. The sensitivity analysis indicated stability of the lifetime costs to variation in mean occupancy times, rates of opportunistic diseases, rates of adverse events (AE), and costs. The total annual costs (1995 dollars) of HIV+/AIDS patients ranged from $1,934 (> or = 500), $6,015 (200-499), and $9,031 (50-199), to $25,239 ( < 50). The annual costs of opportunistic diseases are esophageal candidiasis (EC) ($2,194), tuberculosis (TB) ($2,924), cryptococcal meningitis (CM) ($17,264), toxoplasmosis ($17,631), Mycobacterium avium complex (MAC) (+20,153), Non-Hodgkin's lymphoma (NHL) ($22,329), wasting syndrome ($26,676), central nervous system (CNS) lymphoma ($27,333), Pneumocystis carinii pneumonia (PCP) [mild ($3,545), moderate ($4,889), and severe ($32,609)], Kaposi' sarcoma (KS) [mild/moderate ($5,902), and severe ($10,744)], and cytomegalovirus (CMV) retinitis ($100,337). The projected lifetime costs of HIV+/AIDS are $94,726 (annual costs $7,645). Our lower lifetime costs as compared with recent estimates may be due to including resources only for HIV+/AIDS-related treatment and not for non-HIV+/AIDS conditions, as well as reduced resource use resulting from more efficient diagnostic and therapeutic techniques and earlier prophylaxis provided by experienced HIV+/AIDS physicians. Nonetheless, our estimates are consistent with decreasing costs of HIV+/AIDS due to a reduction in the average length of stay and frequency of hospitalizations as well as to replacement of inpatient care by outpatient services.

Improved outcome by identification of high-risk nonocclusive mesenteric ischemia, aggressive reexploration, and delayed anastomosis

BACKGROUND

The factors associated with outcome of patients with nonocclusive mesenteric ischemia are poorly defined.

METHODS

Over a 7-year period, 34 consecutive patients with nonocclusive mesenteric ischemia were identified.

RESULTS

The mean age of the study patients was 63 years (range 31 to 94); 21 of 34 (62%) were men. The mean delay in diagnosis was 31 hours (range 7 hours to 6 days). Seven of 34 (21%) underwent preoperative visceral arteriography. Two of these 7 required surgery, and both died as a result of intestinal infarction. The remaining 27 had the diagnosis made at celiotomy. Among the 29 who were explored, 16 of 29 (55%) had intestinal infarction. Twenty-one of 29 (72%) had segmental bowel injury whereas 8 of 29 (28%) had massive injury. Among those with segmental infarction, primary anastomosis was performed in 12 of 21 patients (57%); 5 of the 12 (42%) died. Nine of 21 patients (43%) underwent delayed anastomosis; 2 of the 9 (22%) died. No patient with massive injury underwent primary anastomosis. Second-look laparotomy was performed on 22 of 29 (76%). Eleven of those 22 (50%) had a further bowel resection. Overall, 16 of 29 (55%) who underwent surgery for nonocclusive mesenteric ischemia are alive.

CONCLUSIONS

Improved survival from nonocclusive mesenteric ischemia is dependent upon the identification of high-risk groups, aggressive reexploration, and delayed intestinal anastomosis.

Localization of the human achaete-scute homolog gene (ASCL1) distal to phenylalanine hydroxylase (PAH) and proximal to tumor rejection antigen (TRA1) on chromosome 12q22-q23

ASCL1, the human achaete-scute homolog, is a helix-loop-helix transcription factor that was previously assigned to chromosome 12 using a rodent-human somatic hybrid panel. We now placed this gene on a yeast artificial chromosome contig encompassing position 119 cM of the Généthon genetic map between the two genes phenylalanine hydroxylase (PAH) and tumor rejection antigen 1 (TRA1). We also localized ASCL1 in the 12q22-q23 cytogenetic interval by using fluorescence in situ hybridization.

Physical mapping of the human ELA1 gene between D12S361 and D12S347 on chromosome 12q13

ELA1, the pancreatic elastase 1 gene, is conserved in mammalian genomes. ELA1 was previously mapped to chromosome 12 using a panel of mouse-human somatic cell hybrids. We now report the physical and cytogenetic localization of the ELA1 gene. On the physical map, ELA1 is adjacent to the polymorphic marker AFMa283yg1 and between D12S361 and D12S347. Using fluorescence in situ hybridization, we determined that ELA1 maps to 12q13.

Interleukin-1 and oncostatin M in combination promote the release of collagen fragments from bovine nasal cartilage in culture

Interleukin-1 (IL-1) and Oncostatin M (OM) induce a rapid and reproducible release of proteoglycan and collagen fragments from bovine nasal cartilage in culture. Over 90% of the total collagen was released by day 14 compared to a variable release with IL-1 alone. This release was accompanied by the appearance of collagenolytic activity in the medium that cleaved collagen specifically at the one quarter/three quarter position. Tissue inhibitor of metalloproteinases (TIMP-1) activity was low or absent in media from resorbing tissue. The breakdown of cartilage collagen could be prevented by the addition of BB94, a specific matrix metalloproteinase (MMP) inhibitor. These results suggest that T-cell/macrophage products within inflammed joints can interact with pro-inflammatory cytokines and lead to the rapid destruction of connective tissue collagen.

Primary structure, functional expression, and chromosomal localization of the bumetanide-sensitive Na-K-Cl cotransporter in human colon

By moving chloride into epithelial cells, the Na-K-Cl cotransporter aids transcellular movement of chloride across both secretory and absorptive epithelia. Using cDNA probes from the recently identified elasmobranch secretory Na-K-Cl cotransporter (sNKCC1) (Xu, J. C., Lytle, C. Zhu, T. T., Payne, J. A., Benz, E., and Forbush, B., III (1994) Proc. Natl. Acad. Sci. 91, 2201-2205), we have identified the human homologue. By screening cDNA libraries of a human colonic carcinoma line, T84 cell, we identified a sequence of 4115 bases from overlapping clones. The deduced protein is 1212 amino acids in length, and analysis of the primary structure indicates 12 transmembrane segments. The primary structure is 74% identical to sNKCC1, 91% identical to a mouse Na-K-Cl cotransporter (mNKCC1), 58% identical to rabbit and rat renal Na-K-Cl cotransporters (NKCC2), and 43% identical to the thiazide-sensitive Na-Cl cotransporters from flounder urinary bladder and rat kidney. Similar to sNKCC1 and mNKCC1, the 5'-end of the human colonic cotransporter is rich in G + C content. Interestingly, a triple repeat (GCG)7 occurs within the 5'-coding region and contributes to a large alanine repeat (Ala15). Two sites for N-linked glycosylation are predicted on an extracellular loop between putative transmembrane segments 7 and 8. A single potential site for phosphorylation by protein kinase A is present in the predicted cytoplasmic C-terminal domain. Northern blot analysis revealed a 7.4-7.5-kilobase transcript in T84 cells and shark rectal gland and a approximately 7.2-kilobase transcript in mammalian colon, kidney, lung, and stomach. Metaphase spreads from lymphocytes were probed with biotin-labeled cDNA and avidin fluorescein (the cotransporter gene was localized to human chromosome 5 at position 5q23.3). Human embryonic kidney cells stably transfected with the full-length cDNA expressed a approximately 170-kDa protein recognized by anti-cotransporter antibodies. Following treatment with N-glycosidase F, the molecular mass of the expressed protein was similar to that predicted for the core protein from the cDNA sequence (132-kDa) and identical to that of deglycosylated T84 cotransporter (approximately 135-kDa). The stably transfected cells exhibited a approximately 15-fold greater bumetanide-sensitive 86Rb influx than control cells, and this flux required external sodium and chloride. Flux kinetics were consistent with an electroneutral cotransport of 1Na:1K:2Cl. Preincubation in chloride-free media was necessary to activate fully the expressed cotransporter, suggesting a [Cl]-dependent regulatory mechanism.

Low platelet mitochondrial complex I and complex II/III activity in early untreated Parkinson's disease

Following the discovery of inhibition of electron transport complex 1 by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which produces a parkinsonian syndrome in humans, monkeys, and mice, several laboratories have reported abnormalities of complex I and other electron transport complexes (ETCs) in various tissues from patients with Parkinson's disease (PD). Criticism of the significance of these findings in the etiology of PD has centered on whether drug treatments or the debilitation of the disease process itself produced the low ETC activities. We present results from a blinded study of platelet mitochondrial ETC activities in 18 early untreated PD patients and 18 age- and sex-matched controls and in 13 spousal controls. Lower complex I activity in platelet mitochondria of PD patients was seen in early untreated disease and thus cannot be due to debilitation or drug therapy. Home environmental factors seem an unlikely explanation for the reduced complex I activity in PD patients but have not been excluded. Complex II/III activity was also reduced by 20% in PD compared with age-/sex-matched controls. The low complex I and II/III activities in platelet mitochondria appear to be related to the etiology of PD.

Gender differences in attitudes and use of condom availability programs among sexually active students in New York City public high schools

In 1991, the New York City Board of Education expanded HIV/AIDS education to include condom availability in public high schools. A three-year study was initiated to assess the program's impact on student risk behavior, the schools' social environments, and patterns of communication about HIV/AIDS and condoms among students, their parents and teachers in 12 randomly selected New York City high schools. Findings on gender differences in both attitudes and use of the program among sexually active students are reported here. Sexually active girls' attitudes toward using condoms and the condom availability program were more positive than those of sexually active boys, yet boys were more likely to have used the program. Girls reported embarrassment and confidentiality concerns as the main deterrents to using the program. Data suggest that schools need to examine the address gender-specific attitudes that contribute to reluctance to use the program among sexually active girls.

Parents' attitudes and beliefs about HIV/AIDS prevention with condom availability in New York City public high schools

In 1991, the New York City Board of Education expanded HIV/AIDS education to include condom availability in every public high school. The evaluation was designed to examine the impact of the program on students and monitor changes in parent's knowledge, attitudes, and beliefs. Findings are reported from the first wave of data from the parent survey, 716 parents from 12 randomly chosen NYC high schools and 81 parents from 12 focus groups held at six of the schools. Sixty-nine percent of parents believed students should be able to receive condoms at school, although nearly half felt they should have the right to keep their children from doing so. Most believed making condoms available would result in safer sex practices among students who were sexually active. Data suggest parents support the school's role in reducing HIV/AIDS transmission among adolescents and believe making condoms available represents an acceptable component of an HIV/AIDS prevention program.

Large human YACs constructed in a rad52 strain show a reduced rate of chimerism

Current YAC libraries are plagued by a high frequency of chimeras--that is, clones containing fragments from multiple genomic regions. Chimeras are thought to arise largely through recombination in the yeast host cell. If so, the use of recombination-deficient yeast strains, such as rad52 mutants, might be expected to alleviate the problem. Here, we report the construction of megabase-sized human YACs in the rad52 strain MHY5201 and the determination of their rate of chimerism by fluorescence in situ hybridization analysis. Examination of 48 YACs showed a rate of chimerism of at most 8%, whereas YACs constructed in the wildtype host AB1380 showed a rate of about 50%. These results show that it is possible to significantly decrease the rate of YAC chimerism through the use of appropriate yeast host strains.

Organization of the human keratin type II gene cluster at 12q13

Keratin proteins constitute intermediate filaments and are the major differentiation products of mammalian epithelial cells. The epithelial keratins are classified into two groups, type I and type II, and one member of each group is expressed in a given epithelial cell differentiation stage. Mutations in type I and type II keratin genes have now been implicated in three different human genetic disorders, epidermolysis bullosa simplex, epidermolytic hyperkeratosis, and epidermolytic palmoplantar keratoderma. Members of the type I keratins are mapped to human chromosome 17, and the type II keratin genes are mapped to chromosome 12. To understand the organization of the type II keratin genes on chromosome 12, we isolated several yeast artificial chromosomes carrying these keratin genes and examined them in detail. We show that eight already known type II keratin genes are located in a cluster at 12q13, and their relative organization reflects their evolutionary relationship. We also determined that a type I keratin gene, KRT18, is located next to its partner, KRT8, in this cluster. Careful examination of the cluster also revealed that there may be a number of additional keratin genes at this locus that have not been described previously.

Temporal influences on the prediction of postinfarction mortality by heart rate variability: a comparison with the left ventricular ejection fraction

OBJECTIVE

To examine the influence of the duration of follow up on the values of heart rate variability (HRV) and the left ventricular ejection fraction (LVEF) for predicting mortality after infarction.

BACKGROUND

HRV is an index of autonomic balance that identifies patients at a high risk of arrhythmic events. The index is most depressed during the first few weeks after myocardial infarction whereas left ventricular function tends to deteriorate with time.

HYPOTHESIS

The value of depressed HRV measured before discharge from hospital for predicting mortality after infarction should decline with time.

METHODS

The HRV and the LVEF were assessed in 433 survivors of a first acute myocardial infarction: HRV < 20 units and LVEF < 40% were taken as cut off points. Kaplan-Meier survival functions for total cardiac mortality and sudden cardiac death were calculated for the whole five year follow up period and for different intervening periods.

RESULTS

During follow up of four weeks to five years there were 46 (10.6%) deaths and 15 (3.5%) patients died suddenly. Within the whole follow up period, HRV < 20 units and LVEF < 40% were both strongly associated with total cardiac mortality (p < 0.0001), but HRV was an independent predictor of total cardiac mortality only during the first six months of follow up. There were no deaths predicted by HRV < 20 units after the first year of follow up whereas LVEF < 40% had a sensitivity of 43% and a positive predictive accuracy of 9% for predicting death during this period. HRV < 20 units was better than LVEF < 40% in predicting sudden deaths during the first year of follow up but was an independent predictor only of those sudden deaths occurring within six months of infarction.

CONCLUSIONS

The duration of follow up affects the prediction of sudden death and total cardiac mortality from HRV. Reduced HRV as measured before discharge from hospital does not seem to retain independent prognostic value after six months of follow up. These findings have potential implications for the serial evaluation of HRV and for the prevention of sudden death after myocardial infarction.

Practical tips from clinical nurses: opinions about children visiting

Children visiting parents in the ICU is still controversial. Here are six different opinions about children visiting from ICU nurses, an infection control practitioner, and even a parent. All view points are important to consider in providing access of children to their critically ill parents. Interestingly, even nurses who do not generally support child visitation have allowed children's visits in special circumstances and found the experience positive.

Neutrophil dysfunction in end-stage renal failure: reduced response to priming by C5a

We studied the effect of C5a pretreatment on phosphatidyl-inositol-4,5-bisphosphate (PIP2) hydrolysis and on the increase in peak and resting cytosolic calcium levels induced by C5a (0.1 and 10 nM) and/or N-formyl hexapeptide (FLPEP; 10 nM) in neutrophils isolated from patients with end-stage renal failure (ESRF) and those from healthy controls. We also investigated superoxide anion production under the same conditions using the fluorescent para-hydroxyphenylacetic acid assay. The hydrolysis of PIP2 induced by C5a or FLPEP alone was similar in neutrophils from patients with ESRF and in control cells. Likewise, pretreatment of patients' neutrophils with C5a prior to FLPEP did not affect hydrolysis or the increase in cytosolic calcium concentration as shown previously for control neutrophils. Resting calcium levels in both ESRF and control neutrophils, however, were significantly increased after priming with low C5a concentrations. After priming with low C5a, prior to FLPEP, there was also a significant increase in superoxide production. This increase was significantly lower in cells from uremic patients than in those from healthy controls. Our data suggest that priming-induced superoxide production in neutrophils is reduced in patients with ESRF.