Parent management training in a Chinese population: application and outcome

OBJECTIVE

To examine the applicability and outcome of parent management training in a group of Chinese children referred for aggressive and defiant behaviors.

METHOD

Twenty-five children (aged 4-10 years) were assigned to a standardized 8 to 12 sessions of parent management training. Trained child and adolescent psychiatric nurses conducted the treatment. Measures taken at pretreatment, posttreatment, and 4-month follow-up period included the Child Behavior Checklist, direct observation of parent-child interactions, and a parent perception inventory.

RESULTS

Significant therapeutic gains occurred in parent-child interactions, externalizing behaviors, and parents' perception of their parenting behaviors. These were maintained at 4-month follow-up. Fifty-two percent of cases improved to a level below clinical cutoffs. Poor parent-child interactions had stronger correlation with externalizing disturbances than internalizing disturbances. The changes in parent-child interactions had low correlation with the changes in the symptom profiles.

CONCLUSIONS

The data provide preliminary evidence for the efficacy of parent management training for Chinese children with conduct problems. The rationale for its success and modifications to improve its cultural sensitivity are discussed.

Derivation and biological characterization of a molecular clone of SHIV(KU-2) that causes AIDS, neurological disease, and renal disease in rhesus macaques

Previously, we described the derivation of a pathogenic strain of simian-human immunodeficiency virus (SHIV(KU-2)) consisting of the tat, rev, vpu, and env genes of HIV-1 (strain HXB2) in a genetic background of SIV(mac)239 that causes AIDS and productive infection of the CNS in rhesus macaques (Macca mulatta) (Raghavan et al., 1997, Brain Pathol. 7, 851-861). We report here on the characterization of a molecular clone of SHIV(KU-2), designated SHIV(KU-2MC4), that caused CD4(+) T cell loss as well as neurological and renal disease in macaques. DNA sequence analysis of selected SIV regions of SHIV(KU-2MC4) revealed 10 nucleotide changes in the LTR, whereas Gag, Vif, Vpr, Vpx, and Nef had 1, 1, 1, 2, and 13 predicted amino acid substitutions, respectively, compared to SIV(mac)239. DNA sequence analysis of HIV-1 derived regions of SHIV(KU-2MC4) revealed 2, 1, 2, and 18 predicted amino acid substitutions in the Tat, Rev, Vpu, and Env proteins, respectively, when compared to SHIV-4. Unlike the parental SHIV-4, which is not tropic for macrophages, SHIV(KU-2MC4) replicated efficiently in macrophage cultures as determined by p27 assays. However, despite the numerous changes in the Env protein and newly acquired tropism for macrophages, SHIV(KU-2MC4), like the parental SHIV-4, used CXCR4 exclusively as its coreceptor for entry into susceptible cells. Inoculation of SHIV(KU-2MC4) into two rhesus macaques resulted in severe infection in which the numbers of circulating CD4(+) T cells in the blood declined rapidly by 2 weeks postinoculation and virus producing cells in the peripheral blood mononuclear cells were identified throughout the course of infection. At the time of euthanasia (20 and 22 weeks), both macaques had lost a significant amount of weight and had no circulating CD4(+) T cells. In addition, one macaque developed intension tremors and uncoordinated movements. Virological examination of tissues at necropsy revealed active virus replication in both lymphoid and nonlymphoid tissues such as the lung and brain. Histological examination revealed that the induced immunodeficiency was associated with lymphoid depletion of the lymph nodes and spleen, opportunistic infections, lentiviral encephalitis, and severe glomerulosclerosis of the kidney. This molecular clone will serve as the basis for analyzing the molecular determinants through which SHIV(KU-2) causes severe CD4(+) T cell loss, neurological disease, and SHIV nephropathy in rhesus macaques.

An unusual case of breast metastasis from an anorectal melanoma

An unusual case of solitary breast metastasis from a primary anorectal melanoma in a 59-year-old post-menopausal woman is reported. The course and management of melanotic breast metastases is discussed.

Laparoscopic-assisted resection of right-sided colonic carcinoma: a case-control study

BACKGROUND AND OBJECTIVES

Laparoscopic-assisted resection of colorectal carcinoma is technically feasible. Whether it is beneficial to patients is uncertain. This study reviewed the results of laparoscopic-assisted resection in patients with right-sided colonic adenocarcinoma.

METHODS

We attempted laparoscopic-assisted right to extended right hemicolectomy in 28 patients with right-sided colonic carcinoma (study group). The results were compared with 56 matched patients who underwent conventional open resection in the same period (comparative group).

RESULTS

The median follow-up times for the study and comparative groups were 21.4 and 23.5 months, respectively. The operating time was significantly longer (t-test, P < 0.001), whereas the time to resuming normal diet (Mann-Whitney U-test, P < 0.001) and the duration of hospital stay (Mann-Whitney U-test, P = 0.002) were significantly less in the study than in the comparative group. The oncological clearance, in terms of the number of lymph nodes removed and the resection margins, the complication rate, the disease-free rate, and the survival rate were comparable in the two groups.

CONCLUSIONS

We conclude that laparoscopic-assisted resection of right-sided colonic adenocarcinoma has the advantage over open surgery of allowing earlier recovery. However, this is at the expense of a longer operating time.

Thiazole-derived potent, highly bioavailable short duration growth hormone secretagogues

Replacement of the phenyl in 3 with a 2-pyridyl or 4-thiazolyl group resulted in increased potency in the rat pituitary cell GH release assay and in beagles.

Laparoscopic-assisted resection of right-sided colonic carcinoma: a case-control study

BACKGROUND AND OBJECTIVES

Laparoscopic-assisted resection of colorectal carcinoma is technically feasible. Whether it is beneficial to patients is uncertain. This study reviewed the results of laparoscopic-assisted resection in patients with right-sided colonic adenocarcinoma.

METHODS

We attempted laparoscopic-assisted right to extended right hemicolectomy in 28 patients with right-sided colonic carcinoma (study group). The results were compared with 56 matched patients who underwent conventional open resection in the same period (comparative group).

RESULTS

The median follow-up times for the study and comparative groups were 21.4 and 23.5 months, respectively. The operating time was significantly longer (t-test, P < 0.001), whereas the time to resuming normal diet (Mann-Whitney U-test, P < 0.001) and the duration of hospital stay (Mann-Whitney U-test, P = 0.002) were significantly less in the study than in the comparative group. The oncological clearance, in terms of the number of lymph nodes removed and the resection margins, the complication rate, the disease-free rate, and the survival rate were comparable in the two groups.

CONCLUSIONS

We conclude that laparoscopic-assisted resection of right-sided colonic adenocarcinoma has the advantage over open surgery of allowing earlier recovery. However, this is at the expense of a longer operating time.

Applications of the green fluorescent protein as a molecular marker in environmental microorganisms

In this review, we examine numerous applications of the green fluorescent protein (GFP) marker gene in environmental microbiology research. The GFP and its variants are reviewed and applications in plant-microbe interactions, biofilms, biodegradation, bacterial-protozoan interactions, gene transfer, and biosensors are discussed. Methods for detecting GFP-marked cells are also examined. The GFP is a useful marker in environmental microorganisms, allowing new research that will increase our understanding of microorganisms in the environment.

Identification of a fimbriae-associated haemagglutinin from Prevotella intermedia

Prevotella intermedia, a putative periodontopathic microorganism, possesses various types of fimbriae (surface appendages). Some of these surface structures mediate the adherence of the organism to several mammalian erythrocytes, resulting in the agglutination of the erythrocytes. Prevotella intermedia fimbriae were solubilized and separated by preparative SDS gel electrophoresis followed by preparative isoelectric focusing to determine which fimbrial component(s) were responsible for the haemagglutinating activity exhibited by these bacteria. Heat treatment of isolated fractions which exhibited haemagglutinating activity revealed the presence of two types of haemagglutinating activity which were either heat sensitive or resistant. Analysis of isolated fractions, which exhibited haemagglutinating activity that were heat labile, by Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of a 3.8 kD peptide. The purified peptide had a pI of 4.8-5.0. Examination of fractions containing this peptide by electron microscopy showed the presence of fimbriae. Immunogold labelling showed that mouse antibodies raised against the 3.8 kD peptide bound specifically and extensively to P. intermedia fimbriae. It appears that this peptide is a fimbriae-associated haemagglutinin and may represent a major constituent of the fimbriae. Further, fractions exhibiting haemagglutinating activity that were heat resistant, which were recovered at a pH of 3.5 in preparative isoelectric focusing of fimbrial samples, did not possess any detectable major protein bands as shown by analytical gel electrophoresis. However, silver stained gels for the detection of lipopolysaccharide (LPS) revealed the presence of LPS-like components in these fractions. In addition, LPS isolated from whole cells showed a similar electrophoretic pattern and exhibited the haemagglutinating activity that was heat resistant. The results of this study strongly suggest that P. intermedia possesses the machinery to agglutinate erythrocytes, which may be a contributing factor in its colonization in vivo.

Laparoscopic-assisted resection of colorectal carcinoma: five-year audit

INTRODUCTION

The place of laparoscopic-assisted colectomy for colorectal carcinoma is controversial. This study reviewed a consecutive series of patients who underwent laparoscopic-assisted resection of colorectal carcinoma in the past five years.

METHODS

Two hundred seventeen laparoscopic-assisted resections of colorectal carcinoma were attempted starting in April 1992. Initially, we only selected patients with metastatic disease or patients who were older than 65 years. Subsequently, both palliative and curative resections were attempted in patients with a suitable tumor, with no age limitation. Thus, all suitable patients were randomly assigned to received either laparoscopic-assisted or conventional open surgery.

RESULTS

Data collection was completed in 201 patients. In 22 patients open surgery was performed after a diagnostic laparoscopy. In the remaining 179 patients (90 males) in whom laparoscopic dissection was actually performed, the mean follow-up was 19.8 months, and the mean age was 66.3 years. The procedures performed included right hemicolectomy or extended right hemicolectomy (30 patients), transverse colectomy (2 patients), left hemicolectomy (3 patients), sigmoidectomy (48 patients), anterior resection (59 patients), and abdominoperineal resection (37 patients). Thirty-two (17.7 percent) procedures were converted to open surgery. The mean operation time was 203 minutes. The median blood loss was negligible, and the median requirement of transfusion was zero. The median number of postoperative parenteral analgesic injections was three. The median time to resume diet and hospital discharge were four and six days, respectively. The operative mortality was 1.7 percent. The survival rates at four years were 100, 88.3, and 64.5 percent for patients with Dukes A, B, and C disease, respectively. There was only one (0.65 percent) port-site recurrence.

CONCLUSION

Laparoscopic-assisted resection of colorectal carcinoma was technically feasible and safe. It allowed early postoperative recovery with satisfactory long-term survival. This is at the expense of a long operation. Its benefits over the conventional open technique await the results of the randomized trials.

Invasion of human oral epithelial cells by Prevotella intermedia

Invasion of oral epithelial cells by pathogenic oral bacteria may represent an important virulence factor in the progression of periodontal disease. Here we report that a clinical isolate of Prevotella intermedia, strain 17, was found to invade a human oral epithelial cell line (KB), whereas P. intermedia 27, another clinical isolate, and P. intermedia 25611, the type strain, were not found to invade the cell line. Invasion was quantified by the recovery of viable bacteria following a standard antibiotic protection assay and observed by electron microscopy. Cytochalasin D, cycloheximide, monodansylcadaverine, and low temperature (4 degreesC) inhibited the internalization of P. intermedia 17. Antibodies raised against P. intermedia type C fimbriae and against whole cells inhibited invasion, but the anti-type-C-fimbria antibody inhibited invasion to a greater extent than the anti-whole-cell antibody. This work provides evidence that at least one strain of P. intermedia can invade an oral epithelial cell line and that the type C fimbriae and a cytoskeletal rearrangement are required for this invasion.

Evacuation of the pleural cavity with an infant feeding catheter following en bloc resection of hepatocellular carcinoma and involved diaphragm--an institutional experience

En block resection of hepatocellular carcinoma and the involved diaphragm will, towards the end of operation, require evacuation of the pleural cavity, usually with a chest drain. We describe our method and experience of evacuating the pleural cavity, at the time of diaphragmatic repair, with an infant feeding catheter without the need of a chest drain. We have found the method safe and efficacious.

bcl-1 gene rearrangements in mantle cell lymphoma: a comprehensive analysis of 118 cases, including B-5-fixed tissue, by polymerase chain reaction and Southern transfer analysis

We evaluated 118 cases of mantle cell lymphoma by polymerase chain reaction (PCR) for the major translocation cluster (MTC) region and another breakpoint corresponding to probe p94PS, located 24 kb telomeric to the MTC locus on chromosome 11. The specimens included 64 frozen, 19 formalin-fixed, and 9 B-5-fixed lymph nodes and 26 B-5-fixed bone marrow biopsy specimens. We also analyzed DNA from the 64 frozen lymph nodes by Southern transfer analysis (SB) using three separate bcl-1 breakpoint probes. Gene rearrangements were identified in 17 (PCR) and 18 (SB) of 64 frozen lymph nodes and by PCR in 6 of 19 formalin-fixed lymph nodes, 3 of 9 B-5-fixed lymph nodes, and 12 of 26 B-5-fixed bone marrow cores with MTC locus primers and probe. Only one case showed rearrangement with the p11EH probe that corresponds to breakpoints situated 63 kb telomeric to the MTC locus. No rearrangements were detected by PCR or SB for the breakpoint site corresponding to the p94PS probe, but we identified a polymorphic restriction site with HinD III digest in approximately 25% of the cases. In agreement with other studies, these results confirmed that breakpoints in the MTC region of the bcl-1 locus are tightly clustered and associated with 30 to 40% of mantle cell lymphomas. Other breakpoints in the bcl-1 locus seem to be heterogeneous and cannot be detected by PCR or SB with use of existing probes or primer sequences. The most important finding of our study is optimization of the methodology for the detection of immunoglobulin heavy chain gene rearrangement and MTC region breakpoints by PCR from the DNA isolated from B-5-fixed, paraffin-embedded lymph nodes and bone marrow biopsy specimens. The results obtained from these tissues are comparable to those obtained from frozen or formalin-fixed tissue.

Chronology of genetic changes in the vpu, env, and Nef genes of chimeric simian-human immunodeficiency virus (strain HXB2) during acquisition of virulence for pig-tailed macaques

Recently, we developed a highly pathogenic variant of simian-human immunodeficiency virus, SHIV-4 (containing the tat, rev, vpu, and env of the HXB2 strain of HIV-1 in a genetic background of SIVmac239), through a series of four bone marrow-bone marrow passages-first in rhesus monkeys and then in pig-tailed macaques [Joag et al. (1996) J. Virol. 70, 3189-3197]. Inoculation of pig-tailed macaques with this pathogenic virus (SHIVKU-1) causes subtotal elimination of CD4(+) T cells and fatal opportunistic infections, usually within 6 months. Genetic characterization of SHIVKU-1 showed that it has a functional vpu gene (the first codon is ATG vs ACG for the vpu of SHIV-4) and several amino acid substitutions in Env and nef [Stephens et al. (1997) Virology 231, 313-321]. Two pig-tailed macaques, PPc and PQc, were the first to develop a severe loss of CD4(+) T cells and the acquired immune deficiency syndrome and were euthanized at 26 and 105 weeks, respectively. In this report, we analyzed the changes that occurred in the vpu, nef, and env (gp120) genes of the virus used to inoculate macaques PPc and PQc and established the chronology of changes that occurred in these viral genes as these two animals lost their CD4(+) T cells and progressed to develop acquired immune deficiency syndrome. Compared with SHIV-4, the virus used to inoculate macaques PPc and PQc had 0, 3, and 0 consensus amino acid changes in the Vpu, gp120, and Nef, respectively. An analysis of the viral sequences amplified from peripheral blood mononuclear cells samples taken at various times after inoculation of PPc revealed that the vpu had not reverted to an open reading frame (closed vpu, ACG) at 4 weeks after inoculation, but by 16 weeks vpu had reverted to an open reading frame (open vpu, ATG). Macaque PQc, which had a longer course of disease, had a closed vpu at 4 and 16 weeks, but by 28 weeks, both closed and open vpu were detected. From 39 to 105 weeks, only an open vpu was detected. In both macaques, the reversion to an open vpu correlated well with the second phase (major) of CD4(+) T cell loss. An analysis of the nef and env sequences isolated from the same times after inoculation revealed an association between the reversion of vpu to an open reading frame and the accumulation of increased numbers of consensus changes in these two viral proteins. These data suggest that the concomitant reversion of vpu to an open reading frame along with increased substitutions in Nef and gp120 were important genetic changes in the viral genome that were responsible for the increased and highly efficient rate of replication of the virus in CD4(+) T cells and macrophages, which in turn led to elimination of the CD4(+) T cells and profound loss of immunocompetence in the infected animals.

Laparoscopic-assisted vs. open surgery for colorectal cancer: comparative study of immune effects

PURPOSE

Our aim was to test the hypothesis that laparoscopic-assisted resection for colorectal cancer has an immunologic advantage over traditional open surgery.

METHODS

Sixteen patients with colorectal cancer were randomized to undergo laparoscopic-assisted resection or open surgery. Basic patient data were recorded, and serum interleukin-6 levels, relative proportions of lymphocytes, and human leukocyte antigen-DR expression on monocytes were determined at specific time intervals.

RESULTS

Operating time was longer for laparoscopic-assisted resection (P=0.02), but analgesic requirements were less (P=0.04). All patients exhibited the following: interleukin-6 levels increased to a maximum at 4 hours and returned to preoperative levels within 48 hours. This response appeared greater for open resection (mean peak level, 313 vs. 173 pg/ml; P=0.25). Relative granulocytosis (P < 0.001) was seen within 48 hours, which was offset by a decrease in percentage of lymphocytes (P < 0.001). Changes in lymphocyte subfractions were most significant seven days postsurgery: natural killer cells decreased (P=0.003); T cells increased (P=0.008), with elevation in the CD4/CD8 ratio (P=0.003). B cells were largely unchanged at all time periods. Human leukocyte antigen-DR expression on monocytes was significantly less at 48 hours postsurgery (P < 0.001). All changes were reversed within three weeks of surgery. There were no differences when comparing laparoscopic-assisted resection with open surgery.

CONCLUSIONS

Both laparoscopic-assisted resection and open surgery affect the immune response. It would appear that laparoscopic-assisted resection does not have an immunologic advantage over open surgery in patients with colorectal cancer.

Genetic and biochemical analysis of mutacin 1140, a lantibiotic from Streptococcus mutans

Streptococcus mutans JH1000 and its derivatives were previously shown (J. D. Hillman, K. P. Johnson, and B. I. Yaphe, Infect. Immun. 44:141-144, 1984) to produce a low-molecular-weight, broad-spectrum bacteriocin-like inhibitory substance (BLIS). The thermosensitive vector pTV1-OK harboring Tn917 was used to isolate a BLIS-deficient mutant, DM25, and the mutated gene was recovered by shotgun cloning in Escherichia coli. Sequence analysis of insert DNA adjacent to Tn917 led to the identification of four open reading frames including two (lanA and lanB) which have substantial homology to the Staphylococcus epidermidis structural gene (epiA) and a modifying enzyme gene (epiB) for biosynthesis of the lantibiotic epidermin, respectively. Although the BLIS activity could not be recovered from broth cultures, high yields were obtained from a solid medium consisting of Todd-Hewitt broth containing 0.5% agarose that was stab inoculated with JH1140 (a spontaneous mutant of JH1000 that produces threefold-elevated amounts of activity). Agar could not substitute for agarose. Chloroform extraction of the spent medium produced a fraction which yielded two major bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The faster-migrating band was absent in chloroform extracts of the mutant, DM25. The amino acid sequence of this band was determined by Edman sequencing and mass spectroscopy. The results showed that it is a lantibiotic, which we have named mutacin 1140, and that the sequence corresponded to that deduced from the lanA sequence. We observed a number of similarities of mutacin 1140 to epidermin and an S. mutans lantibiotic, B-Ny266, but it appears to have significant differences in the positions of its thioether bridges. It also has other unique features with regard to its leader sequence and posttranslational modification. A proposed structure for mutacin 1140 is presented.

Simian-human immunodeficiency virus (SHIV) containing the nef/long terminal repeat region of the highly virulent SIVsmmPBj14 causes PBj-like activation of cultured resting peripheral blood mononuclear cells, but the chimera showed No increase in virulence

SIVsmmPBj14 is a highly pathogenic lentivirus which causes acute diarrhea, rash, massive lymphocyte proliferation predominantly in the gastrointestinal tract, and death within 7 to 14 days. In cell culture, the virus has mitogenic effects on resting macaque T lymphocytes. In contrast, SIVmac239 causes AIDS in rhesus macaques, generally within 2 years after inoculation. In a previous study, replacement of amino acid residues 17 and 18 of the Nef protein of SIVmac239 with the corresponding amino acid residues of the Nef protein of SIVsmmPBj14 yielded a PBj-like virus that caused extensive activation of resting T lymphocytes in cultures and acute PBj-like disease when inoculated into pig-tailed macaques. This study suggested that nef played a major role in both processes. In this study, we replaced the nef/long terminal repeat (LTR) region of a nonpathogenic simian-human immunodeficiency virus (SHIV), SHIVPPc, with the corresponding region from SIVsmmPBj14 and examined the biological properties of the resultant virus. Like SIVsmmPBj14, SHIVPPcPBjnef caused massive stimulation of resting peripheral blood mononuclear cells (PBMC), which then produced virus in the absence of extraneous interleukin 2. However, when inoculated into macaques, the virus failed to replicate productively or cause disease. Thus, while these results confirmed that the nef/LTR region of SIVsmmPBj14 played a major role in the activation of resting PBMC, duplication of the cellular activation process in macaques may require a further interaction between nef and the envelope glycoprotein of simian immunodeficiency virus because SHIV, containing the envelope of human immunodeficiency virus type 1, failed to cause activation in vivo.

Randomized trial of early versus delayed laparoscopic cholecystectomy for acute cholecystitis

BACKGROUND

The aim of this prospective randomized study was to define the optimum management between early and delayed laparoscopic cholecystectomy for patients with acute cholecystitis.

METHODS

Patients were randomized to receive either early laparoscopic cholecystectomy within 24 h of randomization or initial conservative treatment followed by delayed laparoscopic cholecystectomy 6-8 weeks later.

RESULTS

There were 53 patients in the early group and 51 in the delayed group. There was no significant difference in conversion rate (early 21 per cent versus delayed 24 per cent), postoperative analgesic requirement (1 versus 2 doses) and postoperative complications. However, the early group had significantly longer operating time (122.8 versus 106.6 min, P = 0.04) and shorter total hospital stay (7.6 versus 11.6 days, P < 0.001).

CONCLUSION

Early laparoscopic cholecystectomy is safe and feasible for acute cholecystitis with the additional benefit of shorter total hospital stay. Apart from a shorter operating time, treating patients with delayed laparoscopic cholecystectomy does not offer additional benefit.

In vitro and in vivo evaluations of intestinal barriers for the zwitterion L-767,679 and its carboxyl ester prodrug L-775,318. Roles of efflux and metabolism

The barriers to oral delivery of the hydrophilic zwitterion L-767, 679 (I) and its carboxyl ester prodrug L-775,318 (II) were examined. In the Caco-2 cell model, transport of II, but not I, was strongly oriented in the secretory direction. The basal-to-apical transport of II displayed saturable kinetics and was markedly inhibited by verapamil and quinidine, known P-glycoprotein inhibitors. In Caco-2 cells, metabolism of I was not observed, whereas hydrolysis of II was modest (</=20%). In the in situ rat intestinal loop model, verapamil did not affect the absorption of I but significantly increased the absorption of II. I was resistant to intestinal metabolism, whereas II underwent hydrolysis partially in rat lumen but more extensively in rat intestinal tissue and blood. In vitro metabolism studies indicated that verapamil also inhibited the hydrolysis of II in rats. The inhibition was relatively specific for the intestinal and not the luminal esterases. These results suggested that the intestinal absorption of I was limited not by intestinal efflux or metabolism but more likely by the low lipophilicity of I. However, an efflux system, likely mediated by P-glycoprotein, played an important role in limiting the absorption of II. In rats, metabolism served as an additional barrier to the absorption of II. Verapamil increased the intestinal absorption of the prodrug by inhibiting the efflux system in the two models studied, as well as possibly inhibiting metabolism in rats. For the first time, secretory transport was identified as a cause of the failure to increase the absorption of a lipophilic and cationic prodrug developed to overcome the absorption problem.

A potent, orally bioavailable benzazepinone growth hormone secretagogue

The identification of L-739,943 (8b), a potent, orally bioavailable benzolactam growth hormone secretagogue, is obtained from zwitterionic L-692,429 through modification of its amino acid side chain and replacement of the acidic 2'-tetrazole with the neutral and potency enhancing 2'-(N-methylaminocarbonylamino)methyl substituent. L-739,943 is orally active for the release of growth hormone in beagle dogs at doses as low as 0.5 mg/kg. Oral bioavailability in dogs of 8b is 24% at a dose of 2 mg/kg with a mean drug Cmax of 145 +/- 46 ng/mL. L-739,943 represents a significant breakthrough in terms of both potency and oral bioavailability as compared to the prototype benzolactam L-692,429.

Nucleotide substitutions in the long terminal repeat are not required for development of neurovirulence by simian immunodeficiency virus strain mac

The question of whether consensus nucleotide substitutions in the long terminal repeat (LTR) region of simian immunodeficiency virus strain mac (SIVmac) are important for neurovirulence was investigated in this report. Brains and lymph nodes from two macaques that developed AIDS and encephalitis following inoculation with two strains of neurovirulent SIVmac, and from one animal with AIDS but no neurological disease after inoculation with non-neurovirulent SIVmac239 were used. The 5' LTR regions from neurovirulent SIVmacR71/17E and SIVmac7F-Lu were amplified, cloned and sequenced and these sequences were compared to the LTRs amplified from three regions of the respective encephalitic brains and lymph nodes from macaques inoculated with each virus. The SIVmac7F-Lu and SIVmacR71/17E viruses had zero and three consensus substitutions, respectively, in the U3, R and U5 regions of the LTR compared to that of SIVmac239. The only consensus substitution in the LTR-gag region of the genome was a T to C change at position 829 within the tRNA binding site. The sequences amplified from the brain and lymph nodes of the two animals with AIDS and encephalitis were identical. This single common substitution in this region of the virus genome, the T to C substitution at position 829, was also found in the LTRs isolated from the brain and lymphoid organs from the macaque inoculated with SIVmac239. The virtual identity in nucleotide sequences in the LTR of the neurovirulent and non-neurovirulent viruses and in CNS and lymph tissues of animals inoculated with the viruses suggests that the LTR has no effect on the tissue tropisms of the viruses.