Occupational exposure to pesticides and nerve conduction studies among Korean farmers

This study aimed to determine whether occupational exposure to pesticides was associated with decreased nerve conduction studies among farmers. On 2 separate occasions, the authors performed a cross-sectional study of a group of 31 male farmers who periodically applied pesticides. The study included questionnaire interviews and nerve conduction studies on the median, ulnar, posterior tibial, peroneal, and sural nerves. Although all mean values remained within laboratory normal limits, significant differences between the first and second tests were found in sensory conduction velocities on the median and sural nerves, and motor conduction velocities on the posterior tibial nerve. Lifetime days of pesticide application was negatively associated with nerve conduction velocities at most nerves after adjusting for potential confounders. These findings may reflect a link between occupational pesticide exposure and peripheral neurophysiologic abnormality that deserves further evaluation.

Effects of triethyl phosphate and nitrate on electrokinetically enhanced biodegradation of diesel in low permeability soils

Bench-scale experiments for electrokinetically enhanced bioremediation of diesel in low permeability soils were conducted. An electrokinetic reactor (ER) was filled with kaolin that was artificially contaminated with diesel at a level of 2500 mg kg(-1). A constant voltage gradient of 1.0 V cm(-1) was applied. In phosphorus transport experiments, KH2PO4 was not distributed homogeneously along the ER, and most of the transported phosphorus was converted to water-insoluble aluminum phosphate after 12 days of electrokinetic (EK) operation. However, the advancing P front of triethyl phosphate (TEP) progressed with time and resulted in uniform P distribution. The treatments employed in the electrokinetically enhanced bioremediation of diesel were control (no addition of nitrogen and phosphorus), NP (KNO3+ KH2PO4), NT (KNO3+ TEP), UP (urea+ KH2PO4), and UT (urea+TEP). Analysis of effluent collected during the first 12 days of EK operation showed that diesel was not removed from the kaolin. After nutrient delivery, using the EK operation, the ER was transferred into an incubator for the biodegradation process. After 60 days of biodegradation, the concentrations of diesel in the kaolin for the NP, NT, UP, UT, and control treatments were 1356, 1002, 1658, 1612, and 2003 mg kg(-1), respectively. The ratio of biodegraded diesel concentration to initial concentration (2465 mg kg(-1)) in NP, NT, UP, UT, and control were 45.0%, 59.4%, 32.7%, 34.6%, and 18.7%, respectively. This result showed that TEP, treated along with NO3-, was most effective for the biodegradation of diesel. TEP was delivered more efficiently to the target zones and with less phosphorus loss than KH2PO4. However, this facilitated phosphorus delivery was effective in biodegrading diesel under anaerobic conditions only when electron acceptors, such as NO3-, were present.

Oxidative stress during peritoneal dialysis: implications in functional and structural changes in the membrane

Progressive peritoneal fibrosis, membrane hyperpermeability, and ultrafiltration failure have been observed in patients on long-term peritoneal dialysis (PD). The present study tested the hypothesis that reactive oxygen species (ROS) generated by conventional PD solution (PDS) mediate functional and structural alterations of peritoneal membrane in vivo. Sprague-Dawley rats were randomized to control, PDS, PDS with an antioxidant, and PDS with an angiotensin II (Ang II) receptor blocker. Commercial PDS containing 3.86% glucose (20-30 ml) with or without N-acetylcystein (NAC) 10 mM or losartan 5 mg/kg was administered intraperitoneally twice a day for 12 weeks. Control rats received sham injection. Rats treated with PDS had significantly lower drain volume and D(4)/D(0) glucose, but higher D(4)/P(4) creatinine and increased membrane thickness and endothelial NOS (eNOS) expression compared to control rats. Omental transforming growth factor (TGF)-beta1, vascular endothelial growth factor (VEGF), collagen I, and heat-shock protein (hsp) 47 expression and lipid peroxide levels and dialysate VEGF and Ang II concentrations were significantly increased in rats treated with PDS compared to control. All of these changes were prevented by both NAC and losartan. In conclusion, the present study demonstrates that ROS generated by conventional PDS are, in large part, responsible for peritoneal fibrosis and membrane hyperpermeability. We suggest that antioxidants or Ang II receptor blockers may allow better preservation of the structural and functional integrity of the peritoneal membrane during long-term PD.

The use of general anaesthesia for the extraction of children's teeth. Results from two UK dental hospitals

AIM

To study the reasons forgiving children a general anaesthetic (GA) for the extraction of teeth, in two different paediatric dentistry centres and to compare them with draft guidelines disseminated for discussion by the British Society of Paediatric Dentistry (BSPD).

METHODS

Data were collected on children who required GA extractions over a two month period (1st may to 30th June 2004) at the Paediatric Dental Units of Liverpool University Dental Hospital (LUDH) and the University Dental Hospital of Manchester (UDHM). The information collected included date of birth, gender, date of referral, date of assessment and date of GA. The reason for the GA was noted in terms of the proposed BSPD guidelines for short GA.

RESULTS

A total of 264 and 268 children required extractions under GA at LUDH and UDHM respectively. At LUDH the main reason in 189 (72%) children was severe pulpitis requiring immediate relief of pain where a child does not have the intellectual maturity to cope with treatment under local analgesia (LA). This was followed by failed extractions under LA in 53 (20%) children. This reason is not listed under the proposed BSPD guidelines. At UDHM the main reason for GA in 114 (42%) children was symptomatic teeth causing pain in more than two quadrants (or in two quadrants necessitating the use of bilateral inferior dental blocks).

CONCLUSIONS

There were differences in the clinical rationale for GA between children attending the two centres. Further information is needed to refine the proposed guidelines on the use of GA for dental extractions in paediatric dentistry. The guidelines need to be flexible and updated to reflect changes in practice and service provision.

The frequency of repeat general anaesthesia for teeth extractions in children

AIM

The purpose of this study was to determine the frequency of repeat extractions under general anaesthesia (GA) in children.

METHODS

The dental hospital records of patients attending for outpatient GA extractions at Liverpool University Dental Hospital, Liverpool, UK, between January and March 2003 were examined retrospectively. A data collection form was used to record the relevant information.

RESULTS

A total of 278 patients with a mean age of 6.5 years (SD = 2.2 years) were seen for GA extractions. Of those, 33 patients (11.9%) with a mean age of 4.9 years (SD = 2 years) at the time of their initial GA had had a previous or would undergo a subsequent episode of GA extraction. The mean interval between repeat GA was 2.3 years (SD = 1.6 years). Fifteen cases (45.5%) had the repeat GA within 2 years. Radiographs were available as part of the assessment process for 84 (34.3%) of the 245 patients who had had a single episode of GA. However, of the 33 patients who had had a repeat GA, only seven (21.2%) had radiographs available at the time of the initial GA. Regarding the number of teeth extracted, a significant difference (P < 0.01) was found between the number of teeth extracted in patients who had had a single GA (mean = 4.6, SD = 2.5), compared with those extracted at the initial GA for the repeat GA group (mean = 3.2, SD = 2).

CONCLUSION

The frequency of repeat GA is relatively low, but there is a need for appropriate treatment planning incorporating the use of radiographs to reduce this even further.

(AC)(n) polymorphism of aldose reductase gene and diabetic microvascular complications in type 2 diabetes mellitus

Recent studies suggest that the gene encoding aldose reductase, the enzyme that converts glucose to sorbitol, may confer susceptibility to microvascular disease. The aim of this study therefore, was to investigate the relationship between the aldose reductase gene and type 2 diabetic microvascular complications such as diabetic nephropathy and retinopathy. DNA from 127 Korean patients with type 2 diabetes was typed for an (AC)(n) dinucleotide repeat polymorphic marker at the 5'-end of the aldose reductase gene using polymerase chain reaction. No significant difference in the frequency of the putative risk allele Z-2 was found in patients of nephropathy and retinopathy groups compared with the uncomplicated group (32.2, 34.1 vs. 25.1%, respectively, P>0.05). Similarly, no difference was found in the frequency of the putative protective allele Z+2 among any of the study groups. In conclusion, the results of the study in Korean type 2 diabetic patients do not support the hypothesis that polymorphism at the 5' end of the aldose reductase gene contributes to the susceptibility to diabetic microvascular complications.

A case of malignant proliferating trichilemmoma of the scalp with multiple metastases

We report a case of malignant proliferating trichilemmal tumor showing multiple distant metastases. The patient demonstrated a round mass in the right occipital area for 12 months and the lesion grew rapidly to assume 8 x 6.5 x 4 cm in diameter, with areas of superficial erosion and crusting within the recent 3 months. The entire lesion was removed with a wide surgical excision. It recurred on the neck area 4 months after excision and the lesion was removed with surgical resection again. There was evidence of multiple metastases on CNS and mediastinal lymph nodes after 6 months. The patient was treated with cisplatin and etoposide combination chemotherapy and a partial response was achieved.

Children choosing between general anaesthesia or inhalation sedation for dental extractions: the effect on dental anxiety

AIM

To compare the levels of dental anxiety experienced by children having dental extractions using general anaesthesia (GA) with those having extractions using local anaesthesia and inhalation sedation (IHS) when offered a programmed choice between the two techniques prior to treatment.

DESIGN

Structured interview with child at pre-treatment and at one week (approximately) follow up.

SETTING

Community: primary health care centre.

SUBJECTS

Children aged 9-15 years referred to a local NHS Trust dental clinic (n = 88).

INTERVENTION

Child and parent provided with information about IHS and its benefits over GA for the assistance in tolerating extraction of teeth and provided with a choice of procedure.

MAIN OUTCOME MEASURE

An eight question modified child dental anxiety scale.

RESULTS

Full information was received from 76 children giving an 86% response rate. Post-operative dental anxiety was lower in children who had chosen (with their parent) IHS in comparison to those who had chosen general anaesthesia (P < 0.05). Dental anxiety remained unchanged in the group who chose to have their extractions under GA.

CONCLUSION

Children and their parents who select IHS as opposed to GA to assist in extractions demonstrate less psychological distress.

Thrombopoietin is synergistic with other cytokines for expansion of cord blood progenitor cells

We investigated the effects of recombinant human thrombopoietin (TPO) in combination with various cytokines including erythropoietin (EPO), interleukin-3 (IL-3), interleukin-6 (IL-6), and stem cell factor (SCF) on megakaryopoiesis, and the expansion of CD34+CD41a+ cells from human cord blood CD34+ cells with these cytokines under serum-free conditions. Human cord blood CD34+ cells were cultured in Megacult (Stem Cell Technologies Inc. Vancouver, Canada) in the presence of recombinant growth factors. Colony-forming unit-megakaryocyte (CFU-M) colonies were counted on day 14. CD34+CD41a+ and CD34-CD41a+ cell expansion was analyzed using a serum-free liquid culture system for 7 days with recombinant growth factors. TPO alone had a concentration-dependent effect on megakaryocyte colony growth. At concentrations above 1 ng/ml, TPO supported significant CFU-Meg colony formation in a concentration-dependent manner. The combination of TPO plus other cytokines, including EPO, IL-3, and SCF, resulted in a synergistic enhancement of the number of CFU-Meg colonies, but IL-6 failed to enhance the effect of TPO. The number of CD41a+ cells increased after 7 days in liquid culture of human cord blood CD34+ cells with various cytokines (EPO, IL-3, IL-6, SCF) combined with TPO, but SCF plus TPO only resulted in a significant synergistic increment of CD34+CD41a+ cells compared with TPO alone. The results of the present study indicate that EPO, IL-3, and SCF can be synergistic with TPO to stimulate proliferation of CFU-Meg and suggest that SCF plus TPO can expand CD34+CD41a+ cells to effect the rapid recovery of platelets in patients following stem cell transplantation.

Preliminary validation and reliability of the Modified Child Dental Anxiety Scale

An 8-question Modified Child Dental Anxiety Scale was developed to assess children's concerns about specific dental procedures. These dental situations include examination, scale and polish, injection, filling, extraction, and relative and general anaesthesia. A question about how the child felt generally when visiting the dentist was also included. Children (n = 314) from two schools in Liverpool, ages 8 to 15 years, completed a questionnaire including the modified scale, Corah's Dental Anxiety Scale, the Dental Fear Survey Schedule for Children, and background questions (age, sex and previous dental experience). The internal consistency was favourable (alpha = .84) and test-retest reliability acceptable. This initial study suggests that the scale may be useful in trials to assess the benefits of interventions to assist children receive dental treatment.

A case of lymphomatoid papulosis occurred simultaneously with Ki-1-positive anaplastic large cell lymphoma

Lymphomatoid papulosis (LyP) is a chronic self-healing skin eruption that is clinically benign but histologically mimics a malignant lymphoma. However, lymphomatoid papulosis with anaplastic large cell lymphoma responds poorly to medical treatments, including chemotherapies. We experienced a 60-year-old male patient with lymphomatoid papulosis occurred simultaneously with relapsed Ki-1-positive anaplastic large cell lymphoma who was treated with salvage chemotherapy but, unfortunately, failed to be rescued. We report it with a review of the literature.

Needs for dental information of adolescents from an inner city area of Liverpool

The aim of this study was to determine the needs for dental information of adolescents and investigate the relationship of their desire for information with their opinion of who decides to make an appointment with the dentist (ie parent or child). In-depth interviews were conducted with 10 adolescents (aged 14 to 16 years) to derive questions for a questionnaire to assess dental information needs. One hundred and fifty-eight adolescents of similar age attending a secondary school in Liverpool were invited to complete the questionnaire. The results showed that adolescents are interested in finding out more information on different aspects of dental health which included especially: how to keep their teeth for life, about the best toothpaste, what to do in case they sustain dental injury and whether they required an orthodontic appliance. Another important finding was that more than half of the adolescents (57%) felt that they were responsible for taking decisions for their dental attendance. These children expressed a desire to know more about certain dental matters. Information needs of young people are important because of evidence derived from this study suggesting that acquisitiveness for dental information in this group, has possible implications for future patterns of seeking dental care.

The influence of a two-day recruiting course on groups of fifth and sixth formers

The fall in applications to dental schools in the UK has resulted in various recruiting strategies. One such move was the introduction of a two-day residential course for fifth and sixth formers which was first instigated in 1989. This paper describes the course which had been run on four occasions with a total of 160 participants. The results of a survey on the impressions of the course by these participants is reported. It appears that the courses are effective in increasing interest in dentistry in the vast majority of participants.

Childhood leukemia and dental considerations

Leukemia is the major form of cancer in children in Britain and mirrors the percentage of children affected in the USA. This report outlines some of the medical aspects of leukemia and its treatment and gives a guide to the dentist, who may have the responsibility of dealing with leukemic children and their families.

Remineralization of artificial caries-like lesions in human enamel in situ by chewing sorbitol gum

The objective of the study was to determine quantitatively the effect on the potential for in situ remineralization of artificial caries-like lesions in human enamel when sugar-free gum containing mainly sorbitol as sweetener was chewed after meals and snacks. Artificial white-spot lesions were created in extracted human premolars and divided into three parts. One part was used as reference and the other two worn consecutively for two 21-day periods by 10 volunteers in a cast silver band cemented on lower molar teeth and covered with gauze to promote plaque formation. During the experimental periods, the subjects used fluoridated toothpaste twice daily, and consumed three meals (breakfast, lunch, and dinner) and two snacks (selected from chocolate bar, raisins, chocolate wafer, and iced cupcake). Sorbitol gum was chewed for 20 min immediately after each meal or snack during one of the experimental periods. The three parts of the enamel lesions were then sectioned (congruent to 80 microns) and examined together by means of quantitative microradiography and by polarized light microscopy. All estimates of mineral content indicated that significant remineralization occurred and was approximately doubled with gum-chewing. It is suggested that sorbitol gum stimulates salivation, which is responsible for the significantly enhanced remineralization, thus contributing to a therapeutic, caries-preventive effect. Because the gum was chewed immediately after meals and snacks, inhibition of demineralization may also have occurred.

Utilization of a natural tooth in acid-etch bridging

This report reviews nine cases where despite the wide range of treatments applied to the dentition after a traumatic episode, tooth loss was inevitable and the crown of the damaged tooth was used as a pontic for an immediate bridge. Advantages and disadvantages are reviewed.

Monoclonal antibody CI-panHu defines a pan-human cell-surface antigen unique to higher primates

The murine monoclonal antibody CI-panHu reacts strongly with the cell surface of all human cells, including erythrocytes, tumour cells and HLA-A,B,C-negative cell lines. As such, this antibody defines the first pan-human cell-surface antigen reported. The antigenic determinant detected is associated with a protein doublet of 16,000 MW whose expression is restricted to cells from humans, apes and some species of Old World monkeys. Antibody reactivity is not diminished by routine fixation procedures, nor by paraffin-embedding, and the antigenic determinant is relatively protease-resistant. The use of this antibody as a positive control in immunoassays of human cells is discussed.

Molecular basis of the glycoprotein-C-negative phenotype of herpes simplex virus type 1 macroplaque strain

The basis for the inability of the macroplaque (MP) strain of herpes simplex virus type 1 to express mature glycoprotein C (gC) was examined. RNA transfer (Northern) blot analysis with hybridization probes from the region of the herpes simplex virus type 1 DNA known to encode the gC gene indicated that gC mRNA was produced in MP-infected HeLa cells at levels relative to other mRNAs comparable with that seen in KOS-infected cells. Comparative nucleotide sequence analysis of the gC gene from the MP and KOS strains, coupled with the results of recently reported marker rescue experiments, indicates that the inability of MP to produce gC is due to a frameshift mutation in the gC-coding sequence. Because two different (out-of-phase) open reading frames overlap the gC-coding sequence in the region of the mutation, MP mRNA can encode two gC-related polypeptides. Two polypeptides of the predicted size and precipitable by anti-gC antibodies were produced by in vitro translation of MP mRNA. These polypeptides have not been detected in extracts from infected cells with the same antibodies. Comparative nucleotide sequence analyses led to several corrections in the published sequence for the gC gene and the 17,800-molecular-weight polypeptide gene just to the right in KOS DNA. These relatively minor effects on the predicted amino code sequence of gC are tabulated.

Fine mapping of mutations in the fusion-inducing MP strain of herpes simplex virus type 1

Previous studies [W. T. Ruyechan, L. S. Morse, D. M. Knipe, and B. Roizman (1979) J. Virol. 29, 677-697] have shown that multiple mutations are responsible for the mutant phenotypes of herpes simplex virus type 1, strain MP, and have indicated that these mutations may be located on the genome between map coordinates 0.70 and 0.83. Strain MP produces large syncytial (Syn) plaques on many cell types and does not express glycoprotein C (gC-), whereas a sibling strain mP produces wild-type, small, nonsyncytial (Syn+) plaques and is gC+. Cloned DNA fragments from strains MP and mP (and strain F) were used in marker transfer and marker rescue experiments to map more precisely the mutations in MP. It was found that a 680-bp fragment from MP DNA (map coordinates 0.735 to 0.740) could transfer a Syn marker to mP and that, conversely, an overlapping fragment from mP DNA (map coordinates 0.728 to 0.744) could rescue the Syn mutation of MP. Recombinant viruses obtained in these experiments differed from the donor of the cloned DNA fragment in plaque size, however, indicating that mutation(s) at other regions of the MP genome cause enlarged plaques, in which the infected cells are less rounded than in wild-type plaques. A fragment of MP DNA from map coordinates 0.60 to 0.64 transferred a mutation causing the gC- phenotype to strain mP, and a fragment of F DNA from map coordinates 0.62 to 0.64 rescued the gC- mutation of MP. These results, coupled with data published by Frink et al. [(1983) J. Virol. 45, 643-467], indicate that the mutation responsible for the gC- phenotype of MP may be in the structural gene for gC.

Occlusal variation in Chinese immigrants to the United Kingdom and their offspring

Occlusal variations of immigrant Chinese parents, raised in less developed areas, were compared with their children who were born and bred in the United Kingdom. Of 11 occlusal traits, nine were significantly more variable or less well developed in the offspring. Because genetic factors were unchanged, the deterioration in occlusion in the offspring indicates environmental influences such as dietary consistency, premature deciduous tooth loss from caries and oral respiration.

Anti-gD monoclonal antibodies inhibit cell fusion induced by herpes simplex virus type 1

Monoclonal antibodies directed against glycoprotein D of herpes simplex virus completely inhibited fusion of Vero cells infected with type 1 virus. In contrast, several monoclonal antibodies directed against other viral glycoproteins, including B, were ineffective or were only minimally inhibitory at the highest concentrations tested.

Expression of herpes simplex virus glycoprotein C from a DNA fragment inserted into the thymidine kinase gene of this virus

Previous reports have described mutants of herpes simplex virus type 1 that fail to produce or accumulate one of the major glycoproteins, glycoprotein C (gC). This defect is not lethal in cell culture, has been associated with the syncytial plaque morphology of some mutants, and may result from mutations that map to a region on the genome noncontiguous with the structural gene for gC. To investigate the conditions required for, and consequences of, gC expression in a specific genetic background, we have inserted a wild-type allele of the gC gene into the thymidine kinase gene (tk) of a gC- fusion-inducing viral mutant, strain MP. This was accomplished by identifying cloned viral DNA fragments homologous to gC mRNA, inserting the appropriate fragments into the viral tk cloned in pBR322, and then cotransfecting cells with the recombinant plasmids and DNA from strain MP, for selection of insertional TK- mutants. All TK- mutants containing insertions of appropriate sequences (in either orientation) into tk were found to express gC while maintaining the syncytial plaque morphology of strain MP. Elimination of the insertion from one of the TK- mutants was accompanied by loss of ability to produce gC. Our results permit more precise mapping of the DNA sequence encoding gC, to a subfragment of Sal I fragment R (map coordinates 0.620-0.640) and indicate also that promoter sequences for the gC gene may be located in this fragment. Moreover, we can conclude that the previously described regulatory mutation of strain MP does not prevent expression of gC from the DNA inserted into its gene tk and that the syncytial phenotype of MP cannot be due solely to absence of gC.

Location of the structural genes for glycoproteins gD and gE and for other polypeptides in the S component of herpes simplex virus type 1 DNA

To map the structural genes for the gD and gE polypeptides and for other viral products encoded in the S component of herpes simplex virus type 1 DNA, we selected mRNAs capable of hybridizing to cloned viral DNA fragments and translated the mRNAs in vitro to determine which polypeptides were encoded therein. The gD and gE polypeptides were identified by immunoprecipitation with appropriate monoclonal and monospecific antibodies, whereas the other polypeptides were characterized only by their electrophoretic mobilities in polyacrylamide gels. We found that gD mRNA hybridized to a single SacI subfragment of BamHI fragment J, whereas gE mRNA hybridized to an adjacent SacI subfragment of BamHI fragment J and also to BamHI fragment X. These and other results permit the conclusion that the structural gene for gD is located between map coordinates 0.911 and 0.924, and the gene for gE is between map coordinates 0.924 and 0.951. We also found that mRNAs for polypeptides of 55,000, 42,000, 33,000, and 22,000 molecular weight hybridized to DNA fragments spanning the regions from map coordinates 0.911 to 0.924, 0.897 to 0.911, 0.939 to 0.965, and 0.939 to 0.965, respectively. Finally, in accord with the results of others, we found that mRNA for a 68,000-molecular-weight polypeptide hybridized to the two noncontiguous BamHI fragments N and Z, which share a reiterated DNA sequence.

Evaluating candidates for ventricular aneurysmectomy

Forty consecutive patients having left ventricular (LV) aneurysmectomy were evaluated for surgical risk predictors and were then followed up after operation. Factors evaluated included age, time since last myocardial infarction, NYHA classification, principal indication for surgery, LV end diastolic pressure, LV "A" wave size, number of coronary systems with greater than 70% stenosis, number of coronary bypass grafts, location of aneurysm, and ejection fraction of the nonaneurysmal or "contractile segment," determined by a modification of the method of Watson et al (MCSEF). There was 100% follow-up. There were four perioperative deaths and two late deaths. Operative mortality was 3.4% in patients with MCSEF greater than or equal to 45% and 37.5% in patients with MCSEF less than 45% (P less than .05). None of the other factors evaluated significantly affected mortality independent of MCSEF. Survivors had a mean follow-up of 22 months with a mean improvement in symptoms of 1.6 NYHA class (from 3.3 to 1.7). Forty-four percent have returned to their previous occupations. It is concluded that: (1) the MCSEF is of prime importance in evaluating risk for LV aneurysmectomy; (2) for patients with MCSEF greater than or equal to 45%, LV aneurysmectomy is a low-risk procedure; and (3) LV aneurysmectomy results in sustained relief of symptoms in most patients.

Classification of childhood acute lymphocytic leukaemia using rabbit antisera to leukaemia cells and lymphoblastoid cell lines

Leukaemic cells from seventeen untreated acute lymphocytic leukaemia (A.L.L.) patients have been typed at presentation with heteroantisera prepared in rabbits by complement mediated cytotoxicity. Reactivity with antisera has suggested a preliminary grouping of patients, in this study, into Null, pre-T (post-thymic T-cell precursor) and T-cell subtypes. The leukaemic cells have also been classified with the established markers, E-rosette receptor, surface immunoglobulin and C3 receptor as well as total white cell count at presentation. Anti NALM-1 (Null-lymphoblastoid cell line) serum reacted with cells from all childhood A.L.L. patients tested but could be made specific for cALL antigen of the common Null form of A.L.L. by further absorption or dilution. Antisera to membrane fractions from cells of high white cell count Null-A.L.L. patients reacted with cells of these patients as well as T-A.L.L. patients. Anti MOLT-4 (adult T-A.L.L. derived lymphoblastoid cell line) serum reacted only with cells of T-A.L.L. patients.

Patterns of peptide synthesis in senescent and presenescent human fibroblasts

Peptide production in senescent and presenescent human foreskin fibroblasts was measured using 2-dimensional polyacrylamide gel electrophoresis. This procedure permits the visualization of a cohort of the major peptides being produced. Among this cohort of over 500 peptides only two were found to differ in relative amount in that more was being produced in senescent cells. This difference was confirmed by measurements of the relative intensity of the peptide spot. This difference was senescent cell-specific and not due to the differences in rate of growth of senescent and non-senescent cells.

Growth-related fluctuation in messenger RNA utilization in animal cells

Monkey fibroblasts maintained in culture regulate their levels of intracellular protein throughout the growth cycle by means of variations in the rate of protein biosynthesis. Cytoplasmic mRNA in stationary phase cells was compared to that in exponential phase cells. In stationary phase cells 56% of the cytoplasmic polyadenylated RNA was found in the 40--90S postpolysomal region of sucrose sedimentation gradients, while only 23% was found in this region in exponential phase cells. Analysis of electron micrographs of sectioned exponential and stationary phase cells revealed that this shift in polyadenylated RNA location is accompanied by a loss of polysome-like aggregates of ribosomes. Most if not all of this species of postpolysomal polyadenylated RNA is not being translated by single ribosomes since no detectable amounts of nascent peptide were present in this region. This nonpolysomal polyadenylated RNA is comparable in size to polysomal polyadenylated RNA. The length of the 3'-poly(A) tract was also comparable for these two species. The extent of capping of poly(A)-containing molecules was also comparable for these two species. The template activity of nonpolysomal RNA in a wheat germ extract was comparable to that of polysomal RNA. The peptides produced by these two preparations were of a similar large size. Furthermore, most of the nonpolysomal polyadenylated RNA of stationary phase cells was driven into polysomes in the presence of a low dose of cycloheximide. Therefore, we conclude that the untranslated mRNA that accumulates in stationary phase cells is structurally intact, is fully capable of being translated, and is not being translated due to the operation of a translational initiation block.

Fluctuations in the production of specific cellular peptides during the growth of animal cells

Patterns of newly synthesized proteins of Vero cells in different growth states were obtained using two-dimensional gel electrophoresis. The 240 most prevalent peptide spots were then compared. Cells in exponential growth and in the stationary phase were found to have patterns of peptide spots characteristic of their state of growth. The transition between these patterns is progressive, and the cells acquire a pattern characteristic of quiescent cells by the late exponential phase. These observations suggest that a series of modulations in gene expression occurs during the transition of growth states in animal cells that leads to the specific appearance or disappearance of certain cellular peptides.

Protein metabolism during growth of Vero Cells

Protein synthesis and degradation were studied throughout a growth cycle of Vero cells. The rate of protein synthesis, measured as the rate of amino acid incorporation, reached a maximum at the mid-exponential phase and declined to 10-30% of the maximum in the stationary phase. The rate of protein degradation, measured as the release of radioactive amino acids from uniformly labelled cellular proteins, did not vary in the growth cycle. The amount of protein per cell, measured by an isotopic method, remained constant when normalized to account for the variation in the proportion of actively dividing cells in the cell population during the growth cycle. Cellular protein was determined using this method since it was found that the chemical determination of the amount of protein in the monolayer was not accurate during the early stage of the growth cycle. This was due to a significant amount of serum protein adsorbed to the cells. In this study we were able to show that, in Vero cells, protein synthetic activity is correlated with the rate of cell division, and variations in the rate of synthesis alone are sufficient to meet the changing requirements for cellular protein in a growth cycle.

Prevalence of dental caries of Chinese in Liverpool

The dental caries prevalence of adult Chinese immigrants in the Liverpool area is considerably lower than that of the native British. This is in contrast to Chinese children born in the U.K. who appear to have a higher prevalence compared to the same age group of British children.

Treatment of headache employing acupuncture

In this article, the etiology and acupuncture treatment methods for various forms of headache according to both traditional and contemporary Chinese formulations is presented.

A study of electrical stimulation of acupuncture locus tsusanli (St-36) on mesenteric microcirculation

The effect of low threshold electrical stimulation via acupuncture of classical acupuncture locus tsusanli was studied in rats with light anesthesia. A remarkable decrease of RBC velocities in mesenteric vessels and a fall of carotid arterial pressure occurred during stimulation. An inhibition of sympathetic vasoconstrictor activity by stimulating the conventional meridian loci was the mechanism which could be justifiably postulated.