Detection of SARS-CoV-2 in aerosols in long term care facilities and other indoor spaces with known COVID-19 outbreaks.

Coronavirus outbreaks are likely to occur in crowded and congregate indoor spaces, and their effects are most severe in vulnerable long term care facilities (LTCFs) residents. Public health officers benefit from tools that allow them to control COVID-19 outbreaks in vulnerable settings such as LTCFs, but which could be translated in the future to control other known and future virus outbreaks. This study aims to develop and test a methodology based on detection of SARS-CoV-2 in aerosol samples collected with personal pumps that could be easily implemented by public health officers. The proposed methodology was used to investigate the levels of SARS-CoV-2 in aerosol in indoor settings, mainly focusing on LTCFs, suffering COVID-19 outbreaks, or in the presence of known COVID-19 cases, and targeting the initial days after diagnosis. Aerosol samples (N = 18) were collected between November 2020 and March 2022 in Castelló (Spain) from LTCFs, merchant ships and a private home with recently infected COVID-19 cases. Sampling was performed for 24-h, onto 47 mm polytetrafluoroethylene (PTFE) and quartz filters, connected to personal pumps at 2 and 4 L/min respectively. RNA from filters was extracted and SARS-CoV-2 was determined by detection of regions N1 and N2 of the nucleocapsid gene alongside the E gene using RT-PCR technique. SARS-CoV-2 genetic material was detected in 87.5% samples. Concentrations ranged ND-19,525 gc/m3 (gene E). No genetic traces were detected in rooms from contacts that were isolated as a preventative measure. Very high levels were also measured at locations with poor ventilation. Aerosol measurement conducted with the proposed methodology provided useful information to public health officers and contributed to manage and control 12 different COVID-19 outbreaks. SARS-CoV-2 was detected in aerosol samples collected during outbreaks in congregate spaces. Indoor aerosol sampling is a useful tool in the early detection and management of COVID-19 outbreaks and supports epidemiological investigations.

Acute myocardial infarction: an uncommon complication of takotsubo cardiomyopathy.

Transient left ventricular apical ballooning or Takotsubo syndrome (TS) is characterized by transient left ventricular dysfunction, electrocardiographic changes that mimic acute myocardial infarction (AMI), and minimal release of myocardial enzymes, with no evidence of obstructive coronary artery disease. Although prognosis and outcome are relatively good, reported complications include intraventricular thrombi and embolic events. We report an extremely rare case of AMI complicating the early in-hospital course of a patient with TS.

Siete años de experiencia en pacientes intervenidos por patología proctológica bajo modalidad cirugía mayor ambulatoria y estudio del grado de satisfacción usuaria

Objetivo: Exponer los resultados de 7 años de cirugía proctológica por cirugía mayor ambulatoria (CMA) y determinar el grado de satisfacción usuaria. Material y Método: Se realizó un estudio observacional descriptivo de pacientes sometidos a cirugía proctológica bajo modalidad CMA en el Hospital Regional de Concepción entre los años 2012 y 2019. Se realizó la encuesta telefónica de satisfacción SUCMA-14. Resultados: Se evaluaron a 632 pacientes en el período de estudio. Con diferencias estadísticamente significativas entre patologías para edad, género e IMC. Se aplicó la encuesta a 270 pacientes que contestaron y respondieron. Los resultados mostraron que en general la percepción de los pacientes es positiva salvo puntuales excepciones, como el dolor postoperatorio para condilomas y hemorroides, y las complicaciones postoperatorias para la enfermedad pilonidal. Cuando se realiza el análisis multivariado a los datos correspondientes a la encuesta, no se logran diferencias significativas entre los diagnósticos, pero al aplicarlo a las variables clínico-quirúrgicas se evidencia, claramente, que existe una distinción entre éstas, en especial para la enfermedad pilonidal. Discusión: Las diferencias en términos de tiempos quirúrgicos, complicaciones y re-hospitalizaciones, no necesariamente afectan la percepción que los pacientes tienen de la CMA, ya que ésta depende de otros factores y no solo de los resultados quirúrgicos. Conclusión: Se obtuvieron resultados acorde a la literatura internacional, con peores resultados para enfermedad pilonidal. La satisfacción usuaria fue positiva en general, sin una clara distinción por patologías. Creemos que la CMA es recomendable en patología proctológica tanto por sus resultados, como por la satisfacción que genera en los pacientes.

Objective: To present the results of 7 years of colorectal surgery on mayor ambulatory surgery (MAS) and to determine patient satisfaction. Methods: A descriptive observational study of patients undergoing proctological surgery under the MAS modality was carried out at Regional Hospital of Concepción between 2012 and 2019. The SUCMA-14 satisfaction survey was applied. Results: 632 patients were evaluated in the study period. With statistically significant differences between pathologies for age, gender and BMI. The survey was applied to 270 patients who answered and responded. The results showed that, in general, the perception of the patients is positive, with exceptions, such as postoperative pain for warts and hemorrhoids, and postoperative complications for pilonidal disease. When the multivariate analysis corresponding to the survey is performed, it does not allow distinguishing between the diagnoses, but when applied to the surgical variables, it clearly shows that there is a distinction between them, with a disadvantage for pilonidal disease. Discussion: The differences in terms of surgical times, complications and re-hospitalizations do not necessarily affect the perception that patients have of the MAS, since it depends on other factors and not only on the surgical results. Conclusion: Results were concordant to what is described in the international literature, with worse results for pilonidal disease. Patient satisfaction was positive in general, without a clear distinction by pathology. We believe that MAS is recommended in proctological pathology both for its results and for the satisfaction it generates in patients.

C2 monitoring of cyclosporine in stable renal transplant patients results in lower costs and improved renal function.

INTRODUCTION: C2 (2-hour post-absorption levels) monitoring of cyclosporine (CsA) seems to reduce the rate of acute rejection episodes (ARE) without increasing nephrotoxicity during the first months after transplant. There are a few reports on the impact of adopting this strategy in patients with stable renal transplants. We herein report a prospective trial in long-term renal transplant patients (>6 months) monitored by C0 or C3 who were switched to C2 monitoring. METHODS: Seventy-six (mean age = 43 +/- 11 years) kidney transplant patients (mean = 37 +/- 21 months after transplant) receiving CsA, steroids, and azathioprine were switched to C2 monitoring, seeking to achieve a target range of 800 +/- 100 ng/mL. The patients were followed for at least 6 months. RESULTS: At conversion the C2 values of 61% of the patients were above and 17% below the therapeutic range. Six months after conversion there was a significant reduction in BUN (29 +/- 11 vs 27 +/- 10, P < .01), Creatinine (Cr), cholesterol, and triglyceride levels were unchanged. Mean CsA dose was decreased 10% from 244 +/- 63 to 220 +/- 52 (P < .01), implying a net savings of 390 US dollars per patient per year. Among the group of patients who showed a high C2 level, there was also a reduction in BUN (30 +/- 12 vs 27 +/- 10, P < .01) and a nonsignificant decrease in Cr (1.53 +/- 0.6 vs 1.50 +/- 0.6). CONCLUSIONS: C2 monitoring in stable kidney transplant recipients is feasible and safe. The strategy results in reduced drug costs and improved renal function.

Importance of early adequate exposure to cyclosporine in renal transplant outcome: study of 1-year creatinine.

INTRODUCTION: One-year serum creatinine (SCr) level has been used as a surrogate marker for graft survival in kidney transplantation. We evaluated the importance of different factors on this parameter, emphasizing the importance of adequate exposure to Cyclosporine (CyA). METHODS: Ninety-six consecutive renal transplant recipients who underwent transplantation between 1996 and 2002 were treated with CyA, steroids, and azathioprine. Univariate and multivariate regression analyses were performed for 1-year SCr, acute rejection episodes (ARE), and duration of delayed graft function (DGF). We considered adequate CyA levels within 1 week to be >250 ng/mL trough levels (38%) or 3 hour postdose level (C3) >1100 ng/mL (62%). RESULTS: Mean 1-year SCr was 1.52 +/- 0.5, ARE rate was 27%, and DGF rate was 31%. Overall, 53% of patients achieved adequate exposure to CyA at 1 week (68% on those monitored by C3). Univariate analysis identified female recipient gender, decreasing donor age, absence of ARE, and decreased DGF duration to yield lower 1-year SCr (P < .05). On multivariate analysis for donor age (lower), ARE rate, and duration of DGF (shorter) were the only factors considered to be significant for a lower 1-year SCr level. Multivariate analysis for ARE showed that adequate CyA exposure and lower HLA mismatch decreased ARE, whereas the ability to achieve adequate exposure to CyA and shorter cold ischemia time (CIT) correlated with a reduced incidence of DGF. CONCLUSIONS: One-year SCr level is affected primarily by the incidence of ARE, by donor age, and by duration of DGF. Adequate CyA exposure is related to lower ARE; however, its relation to DGF may be influenced by the reluctance to increase exposure on patients with a nonfunctioning graft.

Benefits of early biopsy on the outcome of kidney transplantation.

INTRODUCTION: Delayed graft function has been associated with worse long-term kidney allograft survival. Adequate diagnosis of the etiology of dysfunction is crucial, often requiring routine early biopsies. The aim of this article was to report the results and safety of early kidney allograft biopsies and how they influenced its management. METHOD: Between September 1994 and July 2004, 134 renal transplant recipients were prescribed cyclosporine (CsA; Neoral, Novartis, Chile), steroids, and a third agent (azathioprine in 92% of the graft recipients). Thirty-four patients (26%) had a kidney biopsy performed within the first week because of allograft dysfunction. RESULTS: The main diagnosis was acute tubular necrosis (ATN) in 22 patients (65%), whereas 6 (18%) were diagnosed with an acute rejection episode (ARE), allowing prompt initiation of therapy with reversal of rejection in 4 of them. Two patients (6%) showed signs of thrombotic microangiopathy (TMA) induced by CsA, which subsided following a switch from CsA to tacrolimus (Prograf Pharmainvesti, Chile). In 2 patients, the biopsy specimen showed signs of CsA nephrotoxicity that reverted following dose reduction. Finally, in 2 patients, the biopsy specimen showed chronic nephropathy of donor origin, which had not been previously recognized, resulting in graft loss. There was only one major complication related to the biopsy, intraperitoneal bleeding that required surgical treatment. CONCLUSIONS: Early allograft biopsy is safe and, in a significant number of cases (30%), it detects important allograft pathology (ARE, TMA, and drug toxicity), which when adequately and promptly treated may rescue the graft.

Validation of the Cross-Cultural Alcoholism Screening Test (CCAST).

BACKGROUND: When screening instruments that are used in the assessment and diagnosis of alcoholism of individuals from different ethnicities, some cultural variables based on norms and societal acceptance of drinking behavior can play an important role in determining the outcome. The accepted diagnostic criteria of current market testing are based on Western standards. METHODS: In this study, the Munich Alcoholism Test (31 items) was the base instrument applied to subjects from several Hispanic-American countries (Bolivia, Chile, Ecuador, Mexico, and Peru). After the sample was submitted to several statistical procedures, these 31 items were reduced to a culture-free, 31-item test named the Cross-Cultural Alcohol Screening Test (CCAST). RESULTS: The results of this Hispanic-American sample (n = 2,107) empirically demonstrated that CCAST measures alcoholism with an adequate degree of accuracy when compared to other available cross-cultural tests. CONCLUSIONS: CCAST is useful in the diagnosis of alcoholism in Spanish-speaking immigrants living in countries where English is spoken. CCAST can be used in general hospitals, psychiatric wards, emergency services and police stations. The test can be useful for other professionals, such as psychological consultants, researchers, and those conducting expertise appraisal.

A simple procedure for isolation of Bufo arenarum C3 complement fraction and preparation of antiserum.

Because of the need for antibodies in our studies involving the third component of complement in Bufo arenarum, we performed a simple procedure to purify C3 from B. arenarum serum to use as antigen in the preparation of the antiserum. The strategy was based on the well-known ability of C3 to bind to zymosan (Zy), a yeast cell wall extract comprised of polysaccharides. The Zy-bound fraction showed cross reactivity with a commercial antibody to human C3 as well as a similar electrophoretic profile (SDS-PAGE) to C3 from other species. The Zy-C3 complex resulting from binding Zy to B. arenarum serum was injected into rabbits and the antiserum against this C3-like fraction was purified by protein A-Sepharose chromatography. The purified C3 antibody was found to be suitable for immunochemical studies.

Involvement of blood serum in amphibian fertilization.

A proteolytic enzyme secreted by the first portion of amphibian oviduct, pars recta, called oviductin in Xenopus laevis, causes ultrastructural alterations on the extracellular matrix of coelomic eggs, turning them susceptible to fertilization. Although great advances have been made in the field of reproduction, the molecular mechanisms responsible for the fusion between the egg and the sperm are yet to be understood. We have recently demonstrated the presence of proteins from pars recta fluid in blood serum and extracellular matrix of coelomic eggs in Bufo arenarum. Here we show, using immunofluorescence procedures, that blood serum components are present in the extracellular matrix of coelomic and pars recta fluid-conditioned eggs in Bufo arenarum. Furthermore, by assessing the neutralizing effect on the conditioning activity of pars recta fluid on coelomic eggs we found that antibodies against pars recta secretions and blood serum inhibited the effect of sperm-lysin on the vitelline envelope of conditioned oocytes and impaired fertilization by sperm. Thus, serum proteins appear to be implicated in the molecular events that lead to amphibian fertilization.

[Specific mortality rates by DRG and main diagnosis according to CIE-9-MC at a level-II hospital]. / Tasas específicas de mortalidad por GRD y diagnóstico principal según la CIE-9-MC en un hospital de II nivel.

INTRODUCTION: The in hospital mortality is a marker of health care quality. It can be evaluated according by the principal diagnosis of disease or by Diagnosis Related Groups (DRG). OBJECTIVES: Know and to analyze the in hospital mortality and mortality rate (MR) in the patients admitted in the Hospital Morales Meseguer (Murcia) of II level of the INSALUD during 1999. METHODOLOGY: Study of the minimum basic group of data into the hospital. RESULTS: The MR was 3.8% of 508 deaths analyzes, 56.7% corresponded a male. The MR was equal in male (3.6%) and females (3.9%). The medium of age into deaths was 77 years. The numbers of deaths inpatients under 80 years was higher in males (n = 197; 65%) than in lower in female (n = 102; 35%)(p = 0.002). The addition of deaths of Internal Medicine and Intensive Care Unit represent a 70% of cases of deaths occurred in the hospital. The MR was higher in Intensive Care Unit (10.5%) followed by Hematology (6.9%) and Internal Medicine (6.1%). Ten DRG represents of 50% of the causes of deaths, and all of them were DRG of medical categories. The DRG more frequents was 541, Respiratory disorders with complication (n = 61, MR 12.8%), followed by DRG 533. Specific cerebrovascular disorders without Transit isquemic accident (n = 33; MR 34.7%), DRG 123 Acute myocardical infarction (AMI) with death (n = 31; MR 100%), DRG 014 Others disorders of nervous system (n = 27; TM: 10.3%) y DRG 552 Disorders of digestive tract without esophagitis, gastroenteritis and not complicated ulcer (n = 27; MR: 31.0). The main diagnostic more frequent was cerebrovascular diseases (n = 60, MR 12.2%), pneumonia-bronchopneumonia (n = 52, MR 10.9%), chronic obstructive lung disease (n = 36, MR 7.1%), AMI (n = 33, MR 11.5%), and neoplasia of digestive tract (n = 26; MR 8.5%). The MR of woman with AMI (19.5%) was higher than man (7.7%) (p = 0.005), the MR in woman with abdominal hernia (4.3%) was higher than man (0.6%) (p = 0.01), and MR of pyelonephritis and urinary infection in man (4.9%) was higher than woman (0%) (p = 0.008). CONCLUSIONS: The mortality and MR by DRG and main diagnostic is an indicator than permit to know and monitoring the quality of health care.

In vivo virulence of commercial Saccharomyces cerevisiae strains with pathogenicity-associated phenotypical traits.

Two commercial Saccharomyces cerevisiae strains, a baker's strain and the bio-therapeutic agent Ultralevure, have been proposed as a possible exogenous source of human colonization (de Llanos et al., 2004, 2006a). Moreover, these strains express phenotypical traits associated to pathogenicity (de Llanos et al., 2006b). Taking into account that both commercial preparations represent an important source of living S. cerevisiae cells we have performed an in vivo study to evaluate whether there is a potential safety risk to humans. Their virulence was compared with that of other commercial strains with less virulent traits, and with clinical isolates, using two murine models (BALB/c and DBA/2N mice). Burden determination in the brain and kidneys showed that the ability to disseminate, colonize and persist was manifested not only by clinical isolates but also by commercial strains. Among these, the baker's strain and Ultralevure were able to cause the death of BALB/c mice at rates similar to those shown by two of the clinical isolates. These results highlight the pathogenic potential of these strains and show that four-week-old BALB/c mice are an appropriate murine model to study the virulence of yeasts with low or moderate pathogenicity. Furthermore, we have shown the positive effect of an immunosuppressive therapy with cyclophosphamide in the virulence of the baker's strains and Ultralevure but not in the rest of the commercial strains under study. The data suggest that although S. cerevisiae has always been considered a GRAS microorganism, commercial preparations should include only those strains shown to be safe in order to minimize complications in risk groups.

Potential involvement of C(3) complement factor in amphibian fertilization.

We have assessed the potential involvement of C(3), the third complement factor, and its receptor in Bufo arenarum fertilization. We show that a polyclonal antibody against a B. arenarum C(3)-like factor (C(3)Ba) reacts specifically with components of the extracellular matrix (ECM) of coelomic eggs and the cell membrane of uterine eggs. Interestingly, we have identified a 163 kD protein immunoreactive with a monoclonal antibody against the CD11b alpha chain of the human C(3) receptor on the cell membrane of the animal pole of uterine eggs, the site of entry of the sperm, but not in coelomic eggs (CR3Ba). Treatment of coelomic eggs with a pars recta oviductal-like protease, trypsin, induced the translocation of C(3)Ba from the ECM to the cell membrane. Furthermore, inhibition of CR3Ba by trypan blue, as well as inhibition of C(3)Ba by anti-C(3)Ba on uterine eggs impaired fertilization, whereas identical treatment on sperm cells did not alter percentage fertilization. Our results suggest, (A) that changes in the localization of C(3)Ba from the ECM to the cell membrane may be triggered by trypsin-like proteases during passage of eggs through the oviduct; and (B) that C(3)Ba/CR3Ba may be involved in B. arenarum fertilization.

Cloning, nucleotide sequence, expression, and chromosomal location of ldh, the gene encoding L-(+)-lactate dehydrogenase, from Lactococcus lactis.

A gene (designated ldh) that encodes fructose-1,6-bisphosphate-activated L-(+)-lactate dehydrogenase was cloned from Lactococcus lactis subsp. lactis. Plasmids containing ldh conferred fructose-1,6-bisphosphate-activated L-(+)-lactate dehydrogenase activity on Escherichia coli cells. This activity was conferred only when a promoter had been introduced into the plasmid to express the cloned ldh. The nucleotide sequence of ldh predicted a chain length of 324 amino acids and a subunit molecular weight of 34,910 for the enzyme, after removal of the N-terminal methionine residue. Northern analyses of L. lactis subsp. lactis RNA showed that a 4.1-kb transcript hybridized strongly with ldh and that 1.2- and 1.1-kb transcripts hybridized to much lesser extents. Promoter- and terminator-cloning studies in which we used the vectors pGKV210 and pGKV259 in L. lactis subsp. lactis revealed that the 5' flanking DNA of ldh is devoid of transcription initiation signals and that transcription entering the 3' flanking DNA from either direction is efficiently terminated. These data and the data from Northern analyses led to the conclusion that ldh is expressed as the 3' gene of the 4.1-kb transcript and suggested that posttranscriptional processing yielded the shorter transcripts. We determined that ldh is located on the L. lactis subsp. lactis chromosome between coordinates 1.619 and 1.669 of the previously reported physical map (D. L. Tulloch, L. R. Finch, A. J. Hillier, and B. E. Davidson, J. Bacteriol. 173:2768-2775, 1991).

Identification of a novel operon in Lactococcus lactis encoding three enzymes for lactic acid synthesis: phosphofructokinase, pyruvate kinase, and lactate dehydrogenase.

The discovery of a novel multicistronic operon that encodes phosphofructokinase, pyruvate kinase, and lactate dehydrogenase in the lactic acid bacterium Lactococcus lactis is reported. The three genes in the operon, designated pfk, pyk, and ldh, contain 340, 502, and 325 codons, respectively. The intergenic distances are 87 bp between pfk and pyk and 117 bp between pyk and ldh. Plasmids containing pfk and pyk conferred phosphofructokinase and pyruvate kinase activity, respectively, on their host. The identity of ldh was established previously by the same approach (R. M. Llanos, A. J. Hillier, and B. E. Davidson, J. Bacteriol. 174:6956-6964, 1992). Each of the genes is preceded by a potential ribosome binding site. The operon is expressed in a 4.1-kb transcript. The 5' end of the transcript was determined to be a G nucleotide positioned 81 bp upstream from the pfk start codon. The pattern of codon usage within the operon is highly biased, with 11 unused amino acid codons. This degree of bias suggests that the operon is highly expressed. The three proteins encoded on the operon are key enzymes in the Embden-Meyerhoff pathway, the central pathway of energy production and lactic acid synthesis in L. lactis. For this reason, we have called the operon the las (lactic acid synthesis) operon.

Phosphorylation of endogenous and TEST-yolk buffer proteins by intact human sperm.

Protein kinase activity of intact, motile sperm was assessed by measuring the transfer of the terminal phosphate from [32P]ATP to tricholoroacetic acid (TCA)-precipitable casein. The action of TEST (TES and Tris) yolk buffer (TYB) treatment on phosphorylation of sperm and TYB proteins was studied by detecting labelled phosphoproteins by autoradiography of polyacrylamide gel electrophoresis (PAGE). Results demonstrate that intact, forward-motile sperm have cell surface protein kinase activities. Although the difference between the kinase activity of freshly ejaculated sperm incubated in TYB was not significant, the protein phosphorylation during incubation in TYB showed that: (i) specific sperm surface proteins were phosphorylated to different degrees during the course of treatment; (ii) TYB proteins were phosphorylated by sperm during incubation; (iii) solubilised [32P]-labelled surface proteins were similar in molecular weight to TYB-labelled proteins. Taking into account that specific proteins on the human sperm surface undergo phosphorylation during incubation in TYB and that the sperm enzyme also acts specifically on some TYB proteins that become attached to the surface of the sperm, working hypotheses are proposed that suggest some correlation between the preservation of semen in TYB and the phosphorylation of proteins by intact human sperm.

[Ascariasis: comparison of the therapeutic efficacy between paico and albendazole in children from Huaraz]. / Ascaridiasis: Comparación de la eficacia terapeutica entre paico y albendazol en niños de Huaraz.

A therapeutical clinical trial was designed to study the effectiveness of Paico and Albendazole, for the treatment of ascariasis in a group of 60 children, between 3 and 14 years old, from a rural community in Huaraz. It was carried out between May and August, 2000. The sample was randomly divided into 30 cases for Paico and 30 for Albendazole, the criteria for entering the trial being a positive examination for Ascaris lumbricoides in feces. The treatment consisted in Paico juice: 1 ml/Kg for less than 10 Kg, and 2 ml/Kg in larger children, one dose before breakfast, for three consecutive days. The Albendazole was administered in a single dose of 400 mg in those over five years of age, and 200 mg in younger children. The effectiveness was evaluated qualitatively (the disappearance of the ascaris eggs from the feces) and quantitatively (decrease in the parasitic burden); in the stool examinations carried out in all cases on entering the study and 15 days after the treatment. All the stool samples were processed in the Referential Laboratory of the Regional Health Authority in Ancash. The qualitative effectiveness between Paico and Albendazole for the eradication of ascariasis was similar at 86.7%. The quantitative effectiveness was 59.5% for Paico and 58.3% for Albendazole. However, it was observed that, unlike Albedazole, Paico is 100% effective in the treatment of Hymenolepsis nana. Adverse effects were presented in 23.3% of the cases for both drugs. It is concluded that, although Paico and Albendazole have a similar effectiveness against Ascaris lumbricoides, Paico has the additional benefit of being effective against Hymenolepsis nana.

Tubulin binding sites on gamma-tubulin: identification and molecular characterization.

gamma-Tubulin is essential to microtubule organization in eukaryotic cells. It is believed that gamma-tubulin interacts with tubulin to accomplish its cellular functions. However, such an interaction has been difficult to demonstrate and to characterize at the molecular level. gamma-Tubulin is a poorly soluble protein, not amenable to biochemical studies in a purified form as yet. Therefore basic questions concerning the existence and properties of tubulin binding sites on gamma-tubulin have been difficult to address. Here we have performed a systematic search for tubulin binding sites on gamma-tubulin using the SPOT peptide technique. We find a specific interaction of tubulin with six distinct domains on gamma-tubulin. These domains are clustered in the central part of the gamma-tubulin primary amino acid sequence. Synthetic peptides corresponding to the tubulin binding domains of gamma-tubulin bind with nanomolar K(d)s to tubulin dimers. These peptides do not interfere measurably with microtubule assembly in vitro and associate with microtubules along the polymer length. On the tertiary structure, the gamma-tubulin peptides cluster to surface regions on both sides of the molecule. Using SPOT analysis, we also find peptides interacting with gamma-tubulin in both the alpha- and beta-tubulin subunits. The tubulin peptides cluster to surface regions on both sides of the alpha- and beta- subunits. These data establish gamma-tubulin as a tubulin ligand with unique tubulin-binding properties and suggests that gamma-tubulin and tubulin dimers associate through lateral interactions.