Novel method for studying mRNA phenotypes in single or small numbers of cells

Biological processes, such as growth control, are often governed by biochemical steps involving mRNA transcripts that are short-lived and have a low copy number. Furthermore, the cells involved in these processes are often available in low numbers from in vivo sources. We now report a method that is superior to in situ hybridization, RNA blot analysis, and the nuclease protection assay for the study of short-lived, low-copy-number mRNA transcripts. The method consists of a microprocedure for isolating RNA from one to a few thousand cells and two coupled enzymatic steps: reverse transcription of whole cellular RNA, followed by amplification of the cDNA by a specifically primed polymerase chain reaction to give specific cDNA fragments that can be visualized on agarose gels by ethidium bromide staining. With this method we have detected actin mRNA from a single cell, or less than 100 cRNA molecules, and have quantified differences in RNA concentrations of less than threefold. The reverse transcription reaction products can be divided for the polymerase chain reaction, and several mRNA species can be assayed simultaneously. Therefore, we call the method single-cell mRNA phenotyping. This technique is applicable to the analysis of low-copy-number growth factor transcripts in cells in culture and in vivo.

Activation of silent genes by transposons Tn5 and Tn10

The presence of transposons Tn10 or Tn5 in the genome increases the frequency with which a silent (promoter-less) gene (hisD) is mutationally activated. The activation frequency is increased 5-25-fold by Tn10 and 30-90-fold by Tn5. Activation of the hisD gene is achieved by transposition of the entire transposon or one of its flanking insertion sequences to a region just upstream of the silent gene, between a Rho-dependent termination site in the adjacent hisG gene and the hisD gene. For both Tn5 and Tn10 the component insertion sequences were found to transpose much more frequently than the entire composite element. Transposons Tn5 and Tn10 have previously been shown to carry promoters which direct transcripts into sequences adjacent to their insertion sites.

Ten-year follow-up on the performance of a telemetric intracranial pressure sensor

A permanently implanted epidural sensor has permitted long term telemetric intracranial pressure monitoring in selected neurosurgical patients. The sensor, consisting only of an inductance and a pressure-sensitive capacitance, has been implanted in 127 patients. Of these 127 patients, 13 have continued to have the sensor in place for 4 to 9 years (average, 6.8 +/- 0.44 years). The remaining patients were lost to follow-up or the sensor was removed. The sensor has been evaluated from the standpoint of accuracy, longevity, safety, and stability. Longevity was proven by successful monitoring over periods of years (in 1 patient, at least 9 years). The sensor has been a safe tool; the only morbidity has been two asymptomatic perisensor blood clots in 2 patients. There have been no infections in any of the 127 cases. The stability of the sensor was evaluated by measuring base line drift over time. This rate was 1.0 +/- 0.2 mm H2O/day. Causes of the drift and possible solutions are discussed, and the sensor is compared to other epidural telemetric monitoring systems.

Expression of soluble and fully functional ricin A chain in Escherichia coli is temperature-sensitive

Linkage of ricin A chain (RA) to a cell surface binding antibody or other ligand can result in a potent cytotoxic agent. We expressed the primary sequence for RA in Escherichia coli to facilitate production and to obtain protein free of naturally occurring contaminants, i.e. ricin B chain. Differences in the level of expression and in the characteristics of the expressed protein were noted when several different host/vector systems were tested. Recombinant RA (rRA) was expressed directly under control of the phage lambda major leftward promoter (PL) and the E. coli trp promoter. It was also expressed fused to E. coli alkaline phosphatase sequences, both in the same reading frame for secretion and out-of-reading frame for expression in a cistron-like arrangement. Expression in the PL promoter system, which is temperature-regulated, was achieved at 37 degrees C as well as at 42 degrees C. The protein expressed at these different temperatures had grossly different properties. Whereas rRA expressed at 37 degrees C was soluble and fully active, that produced at 42 degrees C was aggregated, insoluble, and reduced in activity. Soluble rRA could be converted to the insoluble form by incubation at 42 degrees C in vivo, but not in vitro. Hence, this difference in properties does not simply reflect an inherent thermal instability of the protein. Conditions present in vivo, including the possible association with other proteins, are apparently required for this effect on rRA.

Trichomonas vaginalis phenotypic variation occurs only among trichomonads infected with the double-stranded RNA virus

Trichomonas vaginalis isolates were examined for the presence of viral double-stranded RNA (dsRNA) and the property of phenotypic variation. Only the heterogeneous isolates composed of mAb-reactive and -nonreactive organisms, as determined by indirect immunofluorescence and flow cytofluorometry, and capable of phenotypic variation possessed the dsRNA. Both the positive and negative phenotype subpopulations separated from the heterogeneous parent contained equal amounts of the dsRNA. Loss of the dsRNA upon prolonged in vitro cultivation always correlated with the lack of expression of the major immunogen. The data indicate a relationship between the presence of the dsRNA and the ability of the pathogenic human trichomonads to express immunogens on their surfaces and to undergo phenotypic variation.

Cerebral infarction: shortcomings of angiography in the evaluation of intracranial cerebrovascular disease in 25 cases

We studied the utility and limitations of conventional cerebral angiography in 25 patients with cerebral infarction unassociated with extracranial cerebrovascular disease during a 7-year period. In only one-third of cases was the angiogram diagnostic, and in a single case it altered the pre-angiogram diagnosis by revealing a previously unsuspected embolus. Among the cases clinically diagnosed as cerebral emboli, the 2 confirmatory angiograms were performed early (within 48 hours), and demonstrated medium-large or large vessel filling defects. Two-thirds of the negative angiograms in the embolic clinical category were delayed, but there was no statistically relevant predilection for specific vessel size involvement. The category, primary cerebral vasculopathy, comprised the largest group, 10 in all, and one-half had angiographic confirmation despite time delays. Angiographic recognition was dependent on a characteristic picture of vascular involvement, and not on timing or vessel size predilection. Mitral valve prolapse figured prominently in the clinical cases of vasculopathy of uncertain etiology, which contained a total of 4 cases. The 3 cases with nondiagnostic angiograms were all delayed and demonstrated nonspecific radiographic changes. Clinically, these cases demonstrated signs or symptoms of autoimmune dysfunction, raising the specter of primary cerebral vasculopathy as a cause of cerebral infarction, in contrast to recurrent cerebral emboli.

An unusually compact ribosomal DNA repeat in the protozoan Giardia lamblia

The ribosomal RNA (rRNA) genes of the protozoan parasite Giardia lamblia have been analyzed with respect to size, composition and copy number. They are found to be remarkable in several respects. First, the rRNAs themselves are the smallest yet reported for any eukaryotic organism. Second, the genes encoding them are found as an exceptionally small tandemly repeated unit of only 5.4 kilobase-pairs. Third, the genes are extraordinarily G:C rich, even in regions which are highly conserved between all other eukaryotic rRNA genes. Finally, by analogy to other organisms, the 5.8S RNA appears to lack about 15 nucleotides from its 3'-end, a region previously thought to be essential for 5.8S RNA function. We also provide the first estimates of the genomic complexity and total G:C content of this important protozoan pathogen.

Renal toxicity with cumulative doses of cis-diamminedichloroplatinum-II in pediatric patients with osteosarcoma. Effect on creatinine clearance and methotrexate excretion

Sequential corrected creatinine clearance (CCC) evaluations were obtained in 30 patients treated with intra-arterial and/or intravenous cis-diamminedichloroplatinum-II (CDP). The dose was 150 mg/M2 administered with mannitol diuresis at 2 to 3 weekly intervals. Four hundred fifty-three courses were administered (range, 6-18) over 18 months. Patients also were treated with 283 courses of high-dose methotrexate (MTX) and citrovorum factor "rescue" which were interposed between treatments. Deleterious effects of cumulative courses of CDP manifested as progressive reductions in CCC and delayed excretion of serum MTX. Severe MTX toxicity was aborted by augmenting the fluid intake and prolonging citrovorum factor rescue when elevated levels of serum MTX were detected. The first indication of renal induced CDP toxicity occurred with a cumulative dose of 450 mg/M2. At the termination of treatment (cumulative CDP dose over 1050 mg/M2) renal impairment still was present.

Intraoperative CT monitoring during stereotactic brain surgery

This paper reports our experience in performing the entire stereotactic surgical procedure with a CT scanner, which shows that target shifting can occur as the probe approaches the target. Therefore, when sampling of small targets or specific sites within larger targets is desired. CT confirmation of the probe's position ensures that the specific area seen on CT is biopsied.

Sodium-independent binding of L-[3H]proline to hippocampal synaptic membranes

L-[3H]Proline binds specifically and saturably to rat hippocampal synaptic membranes in the absence of inorganic ions. Saturation isotherms constructed in Hepes-Tris buffer best fit a model of a single independent population of binding sites with a dissociation constant of 1.6 microM and maximum density of 16 pmol/mg protein. The rank order of displacement of radioligand by proline analogues suggests that binding sites of this type could be receptors responsible for proline-induced retinal spreading depression and inhibition of memory consolidation.

Stage-specific expression of a homeo box-containing gene in the non-segmented sea urchin embryo

Hybridization of Drosophila homeo box DNA probes to Southern transfers of genomic DNA from the Hawaiian sea urchin Tripneustes gratilla has revealed that the sea urchin genome contains at least five homeo boxes. Examination of the DNA from several individuals shows that the sequences flanking these homeo boxes exhibit little restriction fragment length polymorphism, indicating they are more highly conserved than the majority of sea urchin DNA. Several clones in a T. gratilla genomic DNA library which hybridized with Drosophila homeo box probes were identified, and one found to be transcribed during embryogenesis was selected for further study. Southern transfer hybridizations showed the cloned gene to be single-copy. DNA sequencing of the sea urchin gene defined a homeo box 70-73% homologous to the Drosophila homeo box probes and an encoded homeo domain 78-88% homologous to those encoded by the probes. Hybridization of DNA probes from the sea urchin homeo box-containing gene to Northern transfers of embryonic RNA demonstrated that the gene produces two transcripts of 6.9 kb and 7.7 kb. Transcripts first accumulate at blastula stage and increase to a maximum level at gastrula stage before decreasing considerably in abundance by pluteus stage.

The effects of a supratentorial mass lesion on brain-stem auditory evoked potentials and short latency somatosensory evoked potentials

Nineteen patients with unilateral supratentorial mass lesion and without any evident clinical signs of transtentorial herniation were studied with Computed Tomography (CT), brain-stem evoked potentials (BAEPs) and central conduction time (CCT) of short latency somatosensory evoked potentials (SEPs). Sixteen had tumours, two had intracranial haematoma and one had chronic subdural haematoma. CT detected the initial signs of transtentorial herniation in every case. Preoperative I-V interpeak latency (IPL) was significantly (M + 2SD) prolonged in 26% of cases on the lesion side and in 21% of cases on the opposite side. The mean I-V IPL was significantly prolonged both on the lesion side and the opposite side (P less than 0.01, P less than 0.02, respectively). Suppression of Wave V (M-2SD) was seen only in two cases, however, the mean amplitude of Wave V was significantly decreased both on the lesion side and on the opposite side (P less than 0.001, P less than 0.01, respectively). CCT of SEPs was significantly (M + 2SD) prolonged in 33% of cases on the lesion side and in only 13% on the opposite side. The mean CCT was, however, significantly prolonged both on the lesion and on the opposite side (P less than 0.001, P less than 0.02, respectively). Postoperative I-V IPL was significantly prolonged in only 11% of cases while the mean I-V IPL was still significantly prolonged (P less than 0.01) and the mean amplitude of Wave V was still suppressed (P less than 0.001) on the lesion side.(ABSTRACT TRUNCATED AT 250 WORDS)

Serial delayed cutaneous hypersensitivity skin testing with multiple recall antigens in healthy volunteers: booster effect study

Booster effects on delayed cutaneous hypersensitivity (DCH) responses have been demonstrated for various antigens when DCH is measured by the Mantoux technique. In the present study, we investigated this possibility when assessing DCH responses using the Multitest CMI multipuncture technique with simultaneous injections of seven test antigens and a control. The DCH responses were quantified for each antigen and for the overall DCH response expressed as a DCH score. In a group of healthy volunteers, DCH was repeatedly tested either 1 month apart or 2 months apart at least six times. When volunteers remained healthy, DCH variations were observed with only two of seven tested antigens: streptococcus which slowly decreased (P = .012) and proteus which slowly increased (P = .04). Responses to the other antigens and the DCH score remained stable. In contrast, greater DCH variations were observed when infections occurred. The results with the Multitest CMI multipuncture show that repeated application had minimal booster effect on DCH responses and may be used to evaluate and follow immunocompetence of patients.

Control of primary osteosarcoma with chemotherapy

High-dose methotrexate with citrovorum factor "rescue" (MTX-CF) produced an apparent complete response of the primary tumor in three patients with osteosarcoma. The response was sustained with MTX-CF, intra-arterial cis-diamminedichloroplatinum II (CDP) and Adriamycin (doxorubicin) for 18 months. Treatment was then electively discontinued. Local recurrence occurred in two patients, 6 and 4 months later, respectively. MTX-CF was reinstated and a complete response was again achieved in one patient. This has been maintained for 15+ months with MTX-CF and intra-arterial CDP administered for 13 of the 15+ months. Reinduction with MTX-CF failed in the second relapsed patient but an apparent remission was again achieved with radiation and intra-arterial CDP. This has been maintained with intravenous CDP, cyclophosphamide and phenylalanine mustard for 14+ months. A complete response in the primary tumor was still present in the nonrelapsed patient, 42 months from diagnosis. All patients have remained free of pulmonary metastases, 40+ to 42+ months from diagnosis.

Respective roles of immune and nutritional factors in the priming of the immune response in the elderly

Ninety-six institutionalized elderly (greater than 70 years old) (mean age: 82 +/- 7 years) subjects, negative for tetanus toxoid antibodies were primed with tetanus toxoid vaccination and dinitrochlorobenzene (DNCB). Correlations were studied between some immunological parameters, nutritional parameters prior to immunization and the immune response intensity after it. Levels of tetanus toxoid specific IgG (ELISA assay) were positively correlated with monocyte phagocytosis, DNCB response and prealbumin levels, and negatively correlated with total IgG, monocyte immune degradation and tetanus toxoid lymphocyte stimulation. No correlation was observed with IgA, IgM, PHA stimulation. Tetanus toxoid lymphocyte stimulation correlated positively with response to DNCB, and negatively with tetanus toxoid IgG as well as total IgG. DNCB response correlated with prealbumin, tetanus toxoid IgG and tetanus toxoid lymphocyte stimulation. Therefore, it appears that malnutrition, as measured by prealbumin level, is one of the main factors contributing to the inconstant senile immunodeficiency. Monocyte antigenic degradation function unaltered with age can impair immune response while conserved or increased phagocytosis enhances immune response in the elderly. High total IgG levels were linked with low specific responses to priming antigens. High specific antibody levels also correlated negatively with cellular specific response. It is assumed that regulatory IgG antibody accumulation, likely anti-idiotypic antibodies, play an important role in senile immunological depletion.

Binding sites for L-[3H]glutamate on hippocampal synaptic membranes: three populations differentially affected by chloride and calcium ions

The effects of Cl- and Ca2+ were studied on the specific binding of L-[3H]glutamate to multiple sites on rat hippocampal synaptic membranes. Quisqualate (5 microM) or DL-2-amino-4-phosphonobutyrate (2-APB) (300 microM) was used to discriminate two previously identified classes of binding sites. Saturation isotherms and displacement curves constructed under different ionic conditions suggested that the effects of Cl- and Ca2+ could best be explained by postulating the existence of three major binding site populations in this preparation rather than two. The binding of L-glutamate to Glu A sites exhibits an absolute dependence on Cl-, and Ca2+ markedly increases the maximum density of these sites. Glu A sites bind quisqualate and 2-APB with relatively high affinity. Cl- (47 mM) more than doubles the maximum density of Glu B sites, but Ca2+ appears to have no effect. Glu B sites can be discriminated from the other classes by their relatively low affinity for quisqualate and 2-APB. There is reason to think that the Glu B population is heterogeneous. The novel Glu C population can be virtually selectively labeled by exposing 2-APB-sensitive binding sites to radioligand in Tris-HOAc buffer with Ca2+. Binding of L-[3H]glutamate to these sites is enhanced by both Cl- and Ca2+, but requires neither ion. Ca2+ appears to increase both the affinity of Glu C sites for L-glutamate and their maximum binding site density. In the presence of Ca2+ and Cl-, Glu C sites bind the radioligand with micromolar affinity (KD approximately 2 microM) and high capacity (Bmax approximately 160 pmol/mg protein).(ABSTRACT TRUNCATED AT 250 WORDS)

Regulatory factors specific for adult and embryonic globin genes may govern their expression in erythroleukemia cells

In order to test if trans-acting regulatory factors specific for globin genes of the adult and embryonic stages of development exist in erythroid cells, transcriptionally active embryonic and adult globin genes on the same chromosome were transferred by cell fusion from the human leukemia cell K562 into phenotypically adult mouse erythroleukemia cells. Restriction-fragment-length polymorphisms of the K562 zeta (embryonic) globin genes were used to establish that all three copies of human chromosome 16 present in the K562 cell showed the same pattern of human globin gene expression after transfer to the mouse erythroleukemia cell. Adult (alpha) but not embryonic (zeta) human globin mRNA was detected in all nine of the independently derived mouse erythroleukemia hybrid cells, each of which contained human chromosome 16. Restriction endonuclease studies of the K562 alpha- and zeta-globin genes after transfer into the mouse erythroleukemia cell showed no evidence of rearrangements or deletions that could explain this loss of zeta-globin gene expression. These data suggest that regulation of globin gene expression in these erythroleukemia cells involves trans-acting regulatory factors specific for the adult and embryonic stages of development.

Site-specific mutagenesis of the human interleukin-2 gene: structure-function analysis of the cysteine residues

The gene encoding human interleukin-2 (IL-2) has been cloned from human spleen cells, peripheral blood lymphocytes, and the Jurkat cell line. Nucleotide sequence analysis of the gene revealed that the encoded IL-2 protein has three cysteines located at amino acid residues 58, 105, and 125 of the mature protein. Site-specific mutagenesis procedures were used to modify the IL-2 gene by changing each of the cysteine codons individually to serine codons. Substitution of serine for cysteine residues at either position 58 or 105 of the IL-2 protein substantially reduced biological activity, indicating that the cysteines at these positions are necessary for maintenance of the biologically active conformation and may therefore be linked by a disulfide bridge. The modified IL-2 protein containing a substitution at position 125 retained full biological activity, suggesting that the cysteine at this position is not involved in a disulfide bond and that a free sulfhydryl group at that position is not necessary for receptor binding.

Transductional instability of Tn5-induced mutations: generalized and specialized transduction of Tn5 by bacteriophage P1

Generalized transduction is commonly used to move transposon-induced mutations among bacterial strains by selecting for inheritance of a transposon-encoded resistance determinant. Although complete cotransduction of the resistance determinant and the chromosomal mutation might be expected, it is often found that when Tn5(Kan) insertion mutations are transduced by bacteriophage P1 most of the nonmutant kanamycin-resistant transductants area due to specialized transduction of Tn5. Such P1::Tn5 specialized transducing phage are not found when a mutant Tn5 element lacking a functional transposase is employed.

Osteosarcoma: intra-arterial treatment of the primary tumor with cis-diammine-dichloroplatinum II (CDP). Angiographic, pathologic, and pharmacologic studies

Intra-arterial CDP was utilized to treat the primary tumor in 11 pediatric patients with osteosarcoma and in one with malignant fibrous histiocytoma. The investigation commenced with a phase I-II pilot study in four osteosarcoma patients. A dose of 150 mg/m2 was found to be safe and effective in producing a clinical response. This was followed by a definitive study in the remaining seven osteosarcoma patients and in the one malignant fibrous histiocytoma patient. The results were assessed by specific clinical, pharmacologic, radiographic and pathologic criteria. The overall response in the definitive study was 50% with two patients exhibiting total tumor destruction. The success of intra-arterial CDP was attributed to its ability to achieve high local drug concentration and tumor penetration. This was demonstrated by pharmacologic studies.

[16 cases of faulty stripping for primary varices]

In answer to the question of knowing whether it is dangerous or not to carry out the excision of intact saphenous veins, the authors define what they mean by faulty strippings. They study 16 personal cases of such strippings, taking their pre-, per-, and postoperative statements from the case-histories. In the discussion they consider the "whys and wherefores" of this kind of faulty treatment, and the mediocre results obtained in medium and long term.

Mitochondrial DNA sequences of primates: tempo and mode of evolution

We cloned and sequenced a segment of mitochondrial DNA from human, chimpanzee, gorilla, orangutan, and gibbon. This segment is 896 bp in length, contains the genes for three transfer RNAs and parts of two proteins, and is homologous in all 5 primates. The 5 sequences differ from one another by base substitutions at 283 positions and by a deletion of one base pair. The sequence differences range from 9 to 19% among species, in agreement with estimates from cleavage map comparisons, thus confirming that the rate of mtDNA evolution in primates is 5 to 10 times higher than in nuclear DNA. The most striking new finding to emerge from these comparisons is that transitions greatly outnumber transversions. Ninety-two percent of the differences among the most closely related species (human, chimpanzee, and gorilla) are transitions. For pairs of species with longer divergence times, the observed percentage of transitions falls until, in the case of comparisons between primates and non-primates, it reaches a value of 45. The time dependence is probably due to obliteration of the record of transitions by multiple substitutions at the same nucleotide site. This finding illustrates the importance of choosing closely related species for analysis of evolutionary process. The remarkable bias toward transitions in mtDNA evolution necessitates the revision of equations that correct for multiple substitutions at the same site. With revised equations, we calculated the incidence of silent and replacement substitutions in the two protein-coding genes. The silent substitution rate is 4 to 6 times higher than the replacement rate, indicating strong functional constraints at replacement sites. Moreover, the silent rate for these two genes is about 10% per million years, a value 10 times higher than the silent rate for the nuclear genes studied so far. In addition, the mean substitution rate in the three mitochondrial tRNA genes is at least 100 times higher than in nuclear tRNA genes. Finally, genealogical analysis of the sequence differences supports the view that the human lineage branched off only slightly before the gorilla and chimpanzee lineages diverged and strengthens the hypothesis that humans are more related to gorillas and chimpanzees than is the orangutan.

The structure of a DNA unwinding protein and its complexes with oligodeoxynucleotides by x-ray diffraction

The structure of the gene 5 DNA unwinding protein from bacteriophage fd has been solved to 2.3 A resolution by x-ray diffraction techniques. The molecule contains an extensive cleft region that we have identified as the DNA binding site on the basis of the residues that comprise its surface. The interior of the groove has a rather large number of basic amino acid residues that serve to draw the polynucleotide backbone into the cleft. Arrayed along the external edges of the groove are a number of aromatic amino acid side groups that are in position to stack upon the bases of the DNA and fix it in place. The cleft then acts as an elongated pair of jaws that draws the DNA between them by charge interactions involving the phosphates with the interior lysines and arginines. The jaws then close on the DNA strand through small conformation changes and the rotation of aromatic side-chains into position to stack upon the purines and pyrimidines. Complexes of the gene 5 protein with a variety of oligodeoxynucleotides have been formed and crystallized for x-ray diffraction analysis. The crystallographic parameters of four different unit cells indicate that the fundamental unit of the complex is composed of six gene 5 protein dimers. We believe this aggregate has 622 point group symmetry and is a ring formed by end to end closure of a linear array of six dimers. From our results we have proposed a double helical model for the gene 5 protein-DNA complex in which the protein forms a spindle or core around which the DNA is spooled. 5.0-A x-ray diffraction data from one of the crystalline complexes is currently being analyzed by molecular replacement techniques to obtain what we believe will be the first direct visualization of a protein-deoxyribonucleic acid complex approaching atomic resolution.

The transposition properties of Tn2 in E. coli

We report the characterization of Tn2 transpositions into the chromosome and into an F' lacproB episome of E. coli. When Tn2 transposes into the chromosome a proportion of the insertions result in auxotrophy. These insertions can revert to prototrophs and lose ampicillin resistance concomitantly. However, Tn2 insertions in F' lacproB are often associated with deletions, and it seems probable that insertion and deletion occur simultaneously.

Influenzal acute myositis in the elderly

We report an 84-year-old man with completely regressive acute myositis. The presumed etiology was an Influenza A virus infection, based on the serologic results.

Antiglobulin antibody in the sera of contacts of children with leukaemia

Healthy adults (parents, neighbours, and hospital staff) in close contact with children with leukaemia were found to have a high incidence of positive latex agglutination antiglobulin tests (probably an IgM antiglobulin antibody). This may explain a previous report of a high incidence of IgM anti-EB virus antibodies in parents of leukaemic children, which our results did not confirm (IgM antiglobulin, reacting with IgG anti-EB virus, could have been misinterpreted as IgM anti-EB virus). The antiglobulin antibody probably represents a nonspecific response to an infective agent. Other hospital staff, including those exposed to nonleukaemic children with infections, had a much lower incidence of the antibody, and it may represent a response to the leukaemic process itself, rather than to the infections to which such children are prone. Some leukaemic children have a similar antibody.

[Should external saphenectomy be routine or eclectic? Results of two series compared]

Based on a comparison between one series where external saphenectomy was routine and another series where external saphenectomy was eclectic, the authors give their preference for excision of the external saphenous when it is clearly diseased, and in this way obtain a 99% success rate. In the discussion, they emphasize that the anatomy of the popliteal fossa can vary, and they attempt to define a plan of management in regard to the external saphenous when it is diseased.

Proteus vulgaris agglutination by cystic fibrosis sera

The factor in sera of patients with cystic fibrosis (CF) and their parents which agglutinates Proteus vulgaris has characteristics similar to those of IgG antibody to this organism. Sera of patients without CF who have P. vulgaris infections agglutinate the organism similarly. At present there are too many false-positives in a control population for the test to be widely useful for heterozygote identification.

Crystal structure of 1:1 complex of barbital with 1-methylimidazole

The prediction of a strong hydrogen-bonding interaction between barbital and 1-methylimidazole was confirmed. Two crystal complexes were obtained, 1:1 and 2:1, and the X-ray structure was determined for the 1:1 complex, which is monoclinic, space group P21/c, with a = 12.236(3) A, b = 11.332(4) A, c = 12.495(4) A, and beta = 120.67(1) degrees. The structure contains disk-shaped hydrogen-bonded tetramers with two molecules of each kind. There is a short NH...N hydrogen bond (2.82 A) in which barbiturate provides the NH donor.

Structure of the DNA binding cleft of the gene 5 protein from bacteriophage fd

The structure of the gene 5 DNA unwinding protein from bacteriophage fd has been solved to 2.3-A resolution by X-ray diffraction techniques. The molecule contains an extensive cleft region that we have identified as the DNA binding site on the basis of the residues that comprise its surface. The interior of the groove has a rather large number of basic amino acid residues that serve to draw the polynucleotide backbone into the cleft. Arrayed along the external edges of the groove are a number of aromatic amino acid side groups that are in position to stack upon the bases of the DNA and fix it in place. The structure and binding mechanism as we visualize it appear to be fully consistent with evidence provided by physical-chemical studies of the protein in solution.